Just done mine today didnt have to take alternator off either. Did you use a 10mm socket?? If you take the dipstick holder out (gently) and the 8mm nut off back of alternator so you can remove the thin wires makes it easier. No good hearing this now though but if theres a next time might help

I had three types of rubber gaskets that came with the new Thermostat, none of which really matched the original. I used one of the gaskets it came with and didnt leak but I did c**p myself incase it was going too!