To my complete amazement, the price for the new pot and knob, INCLUDING postage was just over £5. I nearly bit their hand off! Amazing that in 2010, I could buy spares for a pedal that went out of production in 1991, and at a sensible price.
It took about 15 minutes to open the pedal, de-solder the old pot and solder in the new one, and the icing on the cake was that it actually worked afterwards!
Thanks Roland - Well done! You have at least one very happy customer!