So I bought a battered Class 170 in South West Trains livery for just £45 and will be now converting it into a Class 172 in London Overground Livery.
This is will be an interesting project that will keep me occupied for next the couple of months. Feel free to check in now and then to see any progress that I make.

I began by removing the body from the chassis, modellers who have done this before will know that two small pins are connected from the chassis to the body and these must be disconnected before you can continue. After freeing the chassis, I gave it a good clean and removed any muck to improve its performance. I now turn my attention to the body!

First step is disassembling the power car. I've seen a lot of 'how to posts' about rewiring and installation off DCC + Lighting with modellers snipping of wires. It is possible to disassemble it completely without the need to snip anything off.

The roof should just pop from where they are clipped on the body sides.

Unscrew the cast bracket retaining the top headlight. It should then come apart to free the light bulb.

I tried to unscrew the cast bracket for the bottom headlights first but it's recommended that you wait till you remove the cab from the sides first. Removing the cab was by no means an easy tasks as the sides are glued firmly to the cab, some careful prying and a lot of patience was required. In the end, I had to use a wire to try and pry the two pieces apart seeing as I was worried about fatigue from constantly stressing the plastic. The end of the body sides which are glued to the cab is a very narrow strip of plastic which forms part of the drivers cab door. I managed to pry the two pieces apart and the plastic was just beginning to crack in this region. If anyone can recommend any solvents for removing glued joints without harming the plastic in future, that would be great.

Finally you can remove the cast bracket retaining the two bottom light bulbs with ease, and unscrew the circuit board from the body cross brace. I gently pried the body sides from the cross brace which also forms part of the cab door windows. The circuit board and lights can come off with ease and there's no need to snip any wires

Finally, all pieces have been taken apart and are now ready to be modified. Next, we work on the cab.