imperial countersunk bolts, nuts etc

[dazza]

Presumably you can't replace them with something metric, like M3.5 if they're 3.5mm diameter?

The place near me, www.charnwoodfasteners.com seem to have most things - I've had imperial bolts from them for my RC cars. Give them a call...
There's also GI Fasteners LTD not far from them.

3.5mm would be ideal i cant find any they all go m2 m2.5 m3 m4 m5 and so on i will get in touch with them,