When I bought it the boot release only responded about 50% of the time, out of those it would only open about 70% of the time, the other 30% the motor would move but not disengage the lock. As if the motor didn't have enough reach. So I fit a small spacer on the latch to take away some slack in the cable and give the motor more usable travel, that made things worse as the motor struggled to move it and wouldn't release at all. Set it back to stock after that

A couple weeks later we now have a situation where it just won't open at all, I can hear the motor going but it sounds piss weak. The battery seems fine as it can start the car effortlessly

Do these motors get weak over time? is there anything I can do to freshen it up?
At this stage i'm thinking of pulling the cable out and lubricating it, it still seems strange that the motor seems so piss weak

pull the motor out and check if it's gotten dirt and crap inside it. give it a good cleaning if that's the case. you could also pull on the cable to see if it's broken or has a bend in it that prevents it from being pulled. another option is to get yourself another motor (if the cable is fine). i've got a spare one that i'm not doing anything with if you want it.

Possibly the latch is tighter than it should be. Easy adjustment.

Possibly the latch is tighter than it should be. Easy adjustment.

care to elaborate as to how? I couldn't see any adjustment on the latch itself

So I pulled the cable, smooth as silk but shot it full of WD40 just to make sure
Pulled the motor, operates as expected on its own but still seems piss weak. Pulled it apart (probably not the best idea, getting the preloaded spring back in was a huge pain in the ass) and regreased everything
Blasted the latch all over with Inox. It seems to operate very smoothly with the key
Reassembled, sure enough its craptacular, it just won't release the boot on its own. It's just weak, you can hear the motor struggle to move the latch. So unless the problem exists at the latch and can somehow be adjusted (how?) then I swear it must be the motor itself. Though I don't understand how the motor could go so weak so quickly

If I let it sit for a few minutes, it almost releases. If I repeatedly push the button it gets weaker to the point where it barely moves the cable. That to me says battery, yet the battery is fine and easily starts the car so....

Any other thoughts?

At the moment i'm thinking of installing some sort of circuit board before the motor to overcharge and release more voltage when the button is pressed

Edit: Something I did notice is that the motor has what looks like 2 grooves for 2 seperate cables to thread through. There's 1 which the cable attaches to, and then there's a white plastic piece which sits in front of it that just flops around, though it has a hole and groove for another cable to sit in. Could this be the problem? or is that an unused 'feature'

"Unused feature" is correct, on the Verada the motor works in reverse and the second cable unlatches the petrol flap.

Latch can be adjusted, the mounting holes are elongated and can be moved about. The tension on it needs only be light, like closing the bootlid should just take a little bit of force, play with that adjustment and all will be well. You can judge the force needed by using the key and see how easily it unlocks the lid.

Have you checked the earthing and the power feed?
Sounds like it could be suffering voltage drop, thus reducing the pull the motor has.

Yeah connect it to a spare battery directly. If it works then you probably have a bad ground in the vehicle, or possibly a dirty connector.

Mine did this in the summer time mostly. I ended up just replacing the whole thing, cable & motor. Cable was stripped looking at one point, all the while the motor had seen better days. I think the new one was like 40$.
Did all the same thing, took it apart and greased everything, adjusted the latch, messed with everything I could think of.
Finally gave up and had the old one out and the new one in in about 30 minutes.

Mine lasted about 10 years, and you gotta think, that things been working a lot in those 10 years. Now it opens easily.