A Trilock body sits in the door where an old knob-and-keylock would, and it carries three jobs at once. With the deadbolt withdrawn and the inside button released, it behaves as a plain passage set: the lever or knob turns from either side, and the door opens. Press the button on the inside, and it moves into lockset mode, which locks the outside handle while leaving the inside one free, so anyone in the house can still leave by turning the inside knob or lever. That turn is the panic release.

The third function is a deadbolt with a 20mm throw, meant for the times the house is empty. On the double cylinder version, a key from either side throws or withdraws the bolt. On the single cylinder version, the key works from outside and a turn-button does the job from inside.

All three functions run through one solid brass, double 5-pin Euro-profile cylinder. That is why the key operates every function of the lock: one key, one keyhole, one hand. If you are juggling two keys at the same door, this is the design point that lets you drop the second one.

The 005 deadbolt is a deadbolt on its own. It throws a cut-resistant stainless steel bolt into a box strike that comes with a concealed screw angled across the grain of the door frame, and it has three modes:

- Secure mode: locked from outside and inside, for when nobody is home.

- Safety mode: locked from outside, free to leave from inside.

- Passage mode: the bolt is held back, so the door can be opened from either side.

From the outside, the key selects safety or secure mode via DualSelect: turn the key once for safety mode, then turn it farther for secure mode. From inside, the turn knob sets safety mode and holds the bolt back for passage, while secure mode from inside is set with the key.

Because the 005 is a bolt and nothing more, it does not latch the door. The pull-handle deadbolt model, built around the 005 mechanism, makes that plain: it comes with door magnets to hold the door in place while it sits in passage mode. A hinged door with a 005 still depends on its own latch or lever set to stay closed between lockings, which means two pieces of hardware and, unless they are set to match, two keys.

The Lockwood Paradigm range also includes self-latching pull-handle locksets in single- and double-cylinder versions, in which a deadlatch springs into the strike each time the door closes.

The difference between the two shows most at the moment you leave.

With a Trilock, you close the door and turn the one key to throw the deadbolt. If you only want the door locked while someone is home, the push button on the inside does that before you go, and the door locks from outside as it shuts. The risk to manage is that second case: the button can be pressed and forgotten, and the door is then locked from outside the moment it closes behind someone stepping out to the letterbox.

With a 005 on the door, you lock the latch set (if it locks), then turn the key in the deadbolt and decide how far to turn it. On the inside face, a status indicator called LockAlert shows the current mode at a glance. That indicator answers the "did it catch?" question from the hallway, though not from the car: from outside, you still need to try the handle or turn the key again.

The pull-handle deadbolt model from Lockwood Paradigm works differently again. With no latch, the door rests on its magnets during the day, and locking from outside means throwing the bolt with the key every time you leave.

Both designs provide a mode that keeps the house locked from the outside while leaving the inside free. On a Trilock, that is lockset mode, released by turning the inside handle. On a 005 deadbolt, that is safety mode, where the inside knob turns freely.

Both also have a mode that requires a key on the inside, and that mode applies only to an empty house. On a double cylinder Trilock, the deadbolt thrown by key holds from both sides. On a 005 deadbolt, secure mode does the same. The 005 also has SafetyRelease, which automatically frees the internal knob when you come in through the door, so arriving home and walking inside does not leave you shut in behind a bolt only a key can move. A single-cylinder Trilock avoids the question by placing the turn-button on the inside.

If anyone at home cannot easily find or use a key in a hurry, the inside behaviour matters more than any other detail. Set the deadbolt to its key-from-inside mode only when the house is empty, and use lockset or safety mode whenever someone is inside.

The front door is rarely the only lock you carry a key for. The back door, a side door, and the internal garage door may all have their own cylinders.

The Trilock cylinder can be keyed alike to other Gainsborough products, so one key can run the front entrance set, and other Gainsborough locks around the house. Lockwood Paradigm locks can be keyed alike to other Lockwood door locks, and Lockwood locks can also be set into controlled or specially keyed systems, including keys protected against unauthorised copying and master key systems with different levels of access.

Both keying options stop at the brand's own range. If your back door already has a lock from one brand and the front entrance is being chosen now, the simplest path to a single key is to stay with that brand. Mixing brands may mean two keys on the ring unless a locksmith confirms the cylinders can be set to share a key. Fitting the other doors with cylinders from the same brand as the new front door is another option, and a locksmith can tell you on-site which of your current locks can take one.

Large-format front doors look out of proportion with a small lever, and both makers offer a pull handle for them.

The Trilock Omni pairs a 600mm pull handle with a lever hidden in the exterior design, and the Omni Accent brings a 450mm slimline pull handle to standard-sized doors. Both keep the full three-function Trilock behaviour behind the handle.

The Lockwood Paradigm pull handle measures 600mm outside and 500mm inside, in brushed 304-grade stainless steel, with concealed screw fixings, and is offered in satin stainless steel and matt black. The choice there is between the deadbolt model, which relies on magnets to hold the door in place between lockings, and the self-latching models, which latch the door each time it closes.

Trilock suits a household that wants one key, one keyhole, and one handle to do every job at the front door, with a push-button option for locking from outside while people are home. Lockwood Paradigm suits a household that values seeing the lock's mode at a glance and choosing between safety and secure modes by how far the key turns, and that is comfortable with the deadbolt being separate from whatever holds the door shut day-to-day.

Beyond daily habit, the deciding facts are physical: the thickness of the door, the distance from the door edge to the existing hole, the condition of the frame where the strike will sit, and which brand already holds the other doors in the house. A locksmith measures those on the door, and that measurement settles fit before any finish or handle shape comes into it.

The front door lock is the one you handle every time you come and go, so choose the one whose habits match yours on a rushed morning, then make sure everyone at home knows which mode leaves them free to walk out.