Looking for a machinist to shave off 4mm of a receiver

[Fitch]

Think this is the best place for this post (?)

I've sourced a real steel sliding stock for the Systema TW5 and need to shorten the body slightly to allow the rear pin to slide in and secure it.

The mill just needs to take 4mm off the rear alloy of the receiver body housing (it simply allows the rear stock cap to slide on fully). Its a normal procedure/job for this conversion. Just need a mill.

Shouldn't be difficult at all - just needs to be a 'nice job' rather than attack it with a file or grinder.

I live in the Warwicks area.

I could take it to a local machine shop but am afraid what they might say when asked to work on a realistic looking mp5...

Anyone on here who can do the job for cash?