'squeek' from right rear wheel

Hi, I've got an annoying squeeking sound from the right rear corner. It starts when turning right (unloading the wheel) but then as you drive further/faster becomes more consistent.

I've replaced the rear discs and pads as these were due anyway and thought it may have been related - no difference.

I thought the wheel bearing may be going but I couldn't feel any play - could the bearing be failing but tightening up as oppose to coming loose?

Any help would be appreciated, I've got to drive to Manchester at the weekend and could do without loosing a wheel or going insane from the noise!