Thanks for all the responses. To cover off a few of the points raised: I tried the same setup with another bass (ie same cable, same amp) with no humming, this says to me that it is solely a problem with the bass and not the associated equipment. Secondly, the humming was not present when I bought the bass, it is something that has developed yesterday, 10 days into ownership oddly.
I have seen the threads on how to fix the issue but it strikes me the bass should not be in this position after 10 days of ownership and it almost certainly should not be my responsibility to correct if it fails in that time frame.
I will be returning it to the shop for hopefully a simple fix on their part and I can go on enjoying the bass. I hope they will agree to this because I really don't want to get my money back and have to restart the search for "the one".