Initially I thought it was the brake pads moving in the caliper but all seemed solid.
Next thought was the rollbar bushes so I changed them and the drop links while I was at it even though the old ones hadn't got any play but seemed a bit floppy.
Still had the clicking so checked there was no play in any of the suspension. Nothing there.
So bought a new set of pads from EBC and changed them.
On the passenger side on the outer pad is this little spring clip which obviously keeps the pad tight in the caliper.


Nothing on the drivers side so obviously this was the problem, fortunately the new pads came with new clips so after putting them on both sides the noise has stopped.
There is no mention of this clip in the manual so given that one was missing completely I'm not sure if they should be on the inner or outer pad or perhaps it doesn't matter so long as they are there. Does anyone know for sure which pad they should be on?
Expensive fix for a small problem.
So make sure these little beasties are fitted if you change the pads.