There was an all-in one module that took in coins, sorted them into separate bays and dispensed them when needed by the USB master (what they use in self-checkouts I'm led to believe) but at £150 including delivery it might be a bit too much (depending on what the other quotes come up as)
Any ideas if there was a way to get any of the emulators (MFME preferred) to send some sort of signal out to a board like this? As you guys said putting money in shouldnt be too hard as the software could press a key combo when the switch on the validator (coin slot) is hit (for ex, could hit 0 for a £1, 9 for a 50p etc).
@Jim2311, if you know whether the blog for that is still up that would be greatly appreciated!

The only task at the moment is setting up the skeleton of the cabinet, and adding a metal payout tray underneath where the controls were. I'll be happy to upload pictures later in the project if this forum allows.