Problem I have is I don't know anyone near me who is willing to help.
I'm trying to look for a really cheap engine (petrol engine from anything) to strip down and just learn on.
I obviously don't want to spend huge bucks though.

Sh!t I'd be reluctant to fork out 400 quid for a major organ operation, I would recommend getting a second opinion on your piston. It's not very hard to diagnoses suggested above.

If your not willing to do it, get it back off them and take it to another garage for a second opinion. Granted none of us have seen the bike, but based upon all the symptoms you've described it does not sound anything like they say. Electrical system is the first step. It could also be your starter motor sized, bumping it might have broken the teeth off as already been mentioned.

If they said it could be possible piston damage, I can see 2 possibilities.

1. There taking the piss, either to get money out of you or to get you to take the bike home as they aint interested.

2. There not at all familiar with the VFR V4's and are just making random guesses.

In either of these scenarious I wouldn't want them working on my bike.

If it really is piston / valve damage then fair play, let them or someone else sort it out if you arn't sure. But you can get it back and check all this stuff yourself as long as you know how to hold a screwdriver and a spanner, or take it to another garage for a 2nd opinion if your not confident enough yourself.