I have a few favourite levels that I'd like to play. The pc cheats that I've found dont seem to work any ideas?

If you're talking about the first Cannon Fodder, the level skip cheat provided on most websites actually does work with the GOG version. Go to the map screen, hold Ctrl and type "fodder", then leave the map screen and press Enter.

You probably got thrown off by the white border which is supposed to signal that the cheat has been activated. I also thought the cheat didn't work because I couldn't see the white border on my computer. However, when I completed the process, I still got taken to the next level. The cheat works.

On the amiga I remember a cheat where you saved your game with filename "JOOLSANDJOPS" (think that was itP) and it would upgrade your top 2 troops to the top ranking. Doesn't seem to work on this one though.

I thought the cheat on the amiga was JOOLSTEAM

Haven't checked to see if it works on this version though.

Maybe you confused it with the cheat from Syndicate? IIRC there the cheat to unlock all equipment and gain the ability to freely pick missions was accessed by renaming the company to COOPERTEAM (named after one of the developers, Sean Cooper, and I think the name of your first agent is always Cooper). If you're right about JOOLSTEAM I'd say that this is most likely an homage to Syndicate.