Thank you for your reply and information. I've just been reading the G&L manual again and have noted the settings to which I have added 1/8" as you suggested, so I will have a go with that later. I did adjust the pickups to lower than factory settings the other day, so I may not be that far off anyway.
Yes I did try it through my amp, it didn't sound very good to be honest, but there again my amp never does seem to sound very good in the house. But then I tried my P Bass through the amp as a comparison and that sounded crap as well!
I had much better results through the headphone socket on the amp, and have managed to arrive at some fairly usable settings. I am still finding that I prefer all pickup combinations in Passive mode and with them all in Series. I was able to play with the bass tone control fully on but found it was better with it reduced slightly. I'm still not happy with the treble control, everything really is all in the last 1/4" of the pot's travel, it takes minuscule movements between it being mellow and the treble cutting in. I think I will seriously have to consider changing this.
It was interesting playing the Tribby with the pickups in the neck position and comparing it with my P Bass. Both sounded good, but if you were blindfolded you can tell which one is the P Bass, but they are different types of pickups so I didn't really expect them to sound very close, I think the neck pickups on most basses have a P Bass sound purely down to their position in the body. To sum up, I think it has a very nice P Bass like tone, not a P Bass but nicely different.
I think it is the same with the other pickup combinations, using both pickups together it does not sound like a Jazz Bass and in my opinion is far off it. The bridge pickup you could argue that it has a slight hint of a Stingray tone, I much prefer it to my Jazz Bass bridge pickup soloed.
I feel what would have been better on these basses was a pickup blend control rather than the 3 position pickup selection switch, has anyone carried out this mod (if it is possible)? I imagine it would be a replacement of the volume control with a stacked pot.