Ford Focus Mk1 - Locked keys in the trunk

Hey guys, I probably have a bit of a strange issue/question which might be a long shot but I'm really hoping someone can help me. See below:

Make: Ford
Model: Focus (mk1) hatchback
Year: 2001
Engine: 1.6 Petrol / Manual

Issue: While diagnosing a problem with central locking (trunk lock isn't working via fob, actuator is confirmed dead) I accidentally locked my keys in the trunk.

Unfortunately the car is also deadlocked, so using a reach tool to simply unlock from the inside is not an option and I really want to leave breaking a window as last resort.

I have been doing some research and I am aware of a technique used by auto locksmiths whereby you can hook up the reverse light switch (mounted on the transmission) to a 12v power pack, which then supposedly wakes the car electrical system and from there you can activate the window switches from inside the car (using a long reach tool). Intend to climb through the window and gain access to the trunk. Does anyone have any experience with this?

The reverse light switch has two wires, but I'm not sure how to rig this up to an external power pack and I'm concerned that I may cause damage if connecting it up incorrectly; there is a direct connection to the central fuse box and I'm worried I'll end up blowing a load of them or worse.

I should also mention that the reverse light bulb itself is also blown (waiting for a new bulb to be delivered) but I'm not sure this makes a difference anyway, since the circuit splits before it gets to the bulb and diverts to the Central Fuse Box, before going off to the CTM as you can see in this basic wiring diagram:

https://ibb.co/0CHnMBy

Can anyone point me in the right direction, provide any advice for identifying what wire to apply power to? Or maybe provide other suggestions to wake the system up so I can activate the window switches?

Fords usually unlock by pulling the interior handle.
American market ones do anyway.
Not sure about the technique you mention...

Take the high level stop lamp out n join the two wires together,

Landroverman1958 wrote: Take the high level stop lamp out n join the two wires together,

Thank you sir! I will give this a go, but what is the logic behind this? i.e. what is happening to the vehicle (electrically speaking) when the two wires from the high level brake light are joined?