What Bartolini's fit this Jazz bass
http://www.rondomusic.com/sjb75bmrd.html

Pickup dimensions are: Neck: 3 5/8" x 3/4"Bridge: 3 11/16" x 3/4"

Any info would be much appreciated

(I looked at the Bart website they only had one size)

Thanks

Any of the BARTOLINI 9 series should fit, although you might have to modify the pick guard around the neck pickup slightly. IMO, the Classic Bass singles sound quite nice....