Sir, you are a genius!

I did have 32bit SQL on a 64 bit server and running perfmon.exe brings up the counters.

Now I just need to find out why my tempdb...

Hmm, I didn't have that item at all.

I have added it and set the value to 0 - I'll reboot the server over the weekend and see what happens.

Thanks for this, but when I ran the command it said SQL counters were already installed.

They just don't appear in the Performance Object dropdown.