For anyone still running original wheels and looking to keep to original spec Bridegestones (RE040s), Camskill currently sell both fronts and rears in the correct BZ compound.
Rears are listed at £84.30 each
http://www.camskill....:_2_Noise:_71dB
Fronts are listed at £115.95 each.
http://www.camskill....:_2_Noise:_70dB
A full set, including delivery comes to £414.46.
Hope this helps. I know some have struggled to find stock of both fronts and rears at times.