Cambelt replacement - How many engine mounts removed???

I'm having a bit of a problem with my local dealer.

They changed my cambelt/waterpump and now I have dodgy engine mounts... e.g. they knock.
They are saying its no fault that they've caused, I think it probably is.

Just want to know how many engine mounts need to be removed when doing a cambelt change.

They say one, but I've read two should be removed.
They also say that the engine isn't moved or lifted, just held in place when the mount is removed, and then they can access the cambelt.

This sound right??
Anybody know the correct procedure for changing a cambelt??

Sorry, I know it's asking a lot but it'd help to know what i'm talking about when I no doubt get in an argument with them tomorrow!!

Wouldn't you always have to jack the engine up a bit, no matter which car??
I only ask because....
From my limited (zero) knowledge of these things, but just thinking logically, the engine mounts are squashed between the engine and the chassis (correct??), so to get the mount out you would have to raise the engine a bit to realise it.
Otherwise it would be a bit like trying to pull something from under someone's foot when they are standing on it.... if you catch my drift.