My advice is to strip it back to stock and sell off all the extra's including the freak set as parts. If your left with something that isn't a working marker any more, don't fret as if you scour the wanted ads people are looking for grip frames, the breech, etc etc etc for projects so you can still make some money back on that.
I'll bet if your clever you'll get your £160 and possibly a bit more for your trouble.
I know as I've had do it myself.
I agree, this is the best thing to do. i made about £175 when i sold all my ion bits separately, and it wasn't as upped as yours!
Chris