I then read all the reviews saying that EECH was much better so I ordered that. It came yesterday but I can't get the damn thing to work! I've followed the installation instructions from EECH central to the letter but I get the 'Can't find Diamond tag' error.
That's a bug in the all mods installer. Try installing each mod separately.
As alternative to the allmods I can't use the Mod installer as recommended at EECH Central because I don't have internet access at home (I'm using someone elses PC) so I guess I should manually install the mods. To do this I'm not sure which files I should download. Does anyone know?
Well, you could still use the modinstaller on the PC which has internet access. I'm pretty sure it has an option of just downloading all the mods, and you can then copy all those files and install those on the PC with EECH. Alternatively you should be able to find most (all?) the patches at
http://www.eechcentral.com/files/The most essential however is probably to get the new exe:
http://www.eechcentral.com/files/Game%20patches/Latest%20community%20patches/eechsetup1.8.6.exe ALso, when the game is in a working state (i.e. before I install the allmods) the TrackIr doesn't function. I've tried crafting an eech.ini with (what I believe to be) the correct TrackIR settings but this doesn't seem to work.
Yes, you need a patched exe for track-IR to work.
Finally, is there a way to use two joysticks on EECH? I don't have a fancy controller but in EE2 I was using two joysticks - one for collective and one for cyclic.
Yes, once you have a patched exe you can use as many joysticks you want.