OK - no response to this, but for the benefit of anyone who has the same problem, I offer a solution. I took the bass to my Luthier for a set up and to look at the pickup. He's set it up lovely with TI Jazz flats. He told me the pickups are already potted but suggested the finger noise may be because the pickups were a really tight fit in the scratchplate. He told me that not only does this help the sound transmit from the scratchplate to the pickup, but also, squeezing the case onto the windings increases the pups microphonics. So he's filed out the pickup holes in the scratchplate and - hey presto - problem solved!
With regard the pickup, i really like the sound with the tone rolled off. Fully open it sounds kind of glassy which I'm not overly keen on, but pull a bit of top off and actually, I reckon it sounds ok!