Burpster, thanks for the reply, I have had a look at the wiring diagram. The only difference I can see on my bass is that the black leads from the pups are both soldered on to the control for the neck volume. That is how it was originally, so I've just done the same.
Yes, I have just soldered the white lead to the centre tab. When I now test with a metre there is no reading to that centre tab, so I guess I must have damaged it during the soldering process.
Dont know whether to get a replacement control, but given that will entail additional soldering and the risk of damaging the new one, maybe I should get someone else to do it for me.
Thanks again, as always on this forum the level of help and advice has been great.
All the best Gary.