tilde on extended keyboard

I understand that Cmd plus the tilde key is a shortcut for switching between windows in an application (like within Excel). But the tilde key is supposed to be above the tab key / below the escape. On my keyboard that key gives me § and if I use the shift ±

Command and that key gives nothing, and does not switch me between windows.

My keyboard setting just say "British" (which is correct!)

So how do I switch windows or type a ~ ?

(That one was copied and pasted from Safari!!)

Thanks

Paul