Ok cheers will have a look at the weekend.

clean the discs up and clean out the inner part of the disc that rests against the hub, could be dirt trapped behind there

I would say a warped disc or see if there is any play in any wheel bearings and bottom ball joint

doesn't matter if the discs are new mate. you can warp them on your first run out with new discs on... i did that on mine

The discs & pads are pretty much still new as the car doesn't really do many miles.

The hubs & shafts are standard.

If it was bearings it would cause some kind of noise would it not?

Could be warped disc's or wheel hubs? maybe wheel bearings? check for run out on hubs then disc's. Are you using standard hubs or have you got so called motor sport hubs to use larger drive shafts? As they flex causing vibrations and pad knock back.

Been like this for a while but never really bothered me but just would like to know what could be causeing it?

The car doesn't have ABS and the brake set up i have is calibra turbo calipers with meriva discs & pads.

Any info would be appreciated.