Just to let you know I managed to etch a board and populate it, and against all odds it worked first time! I just implemented a basic counter that flashes some LEDs, but it's a start
I used a crystal oscillator made with a 74HC inverter for the clock.
If anyone else ever wants to do anything similar and is having problems I am happy to pass on the schematics, gerbers etc. Obviously 99% of the time one would get a proper board done, but with the ProASIC3 dev kit costing ~£450 I thought I would save a few quid as I only wanted a basic board to get started with.
Now implementing a 300MHz design in one of my projects is the next step, think I'll be getting that board from my PCB house though..