I've just got a Record 11 speed groupset, i'm advised to only use the official Campag chain tool to join the chain.

It costs £100, i watched a youtube vid on someone demonstrating it, looks to me like you could use a normal one.

Anyone done this? or got an official tool i could lend?

Get your LBS to do it?

Oh, and nice choice of groupset 😀

I thought of this but i like to do stuff myself, i'm researching more on the net 😉

The proper one peens the end of the pin to stop the chain breaking. A normal one won't do that. Depends if you want to take the risk, but considered opinion seems to be it is very likely to break if you don't do this. Park are supposedly bringing out a cheaper tool to do this, though I don't think it's made it across the sea yet, or KMC will have an 11 speed chain shortly. If you want to do it now though you need to either buy or find somebody/LBS with the tool.