Just came across this chat - I'm writing my memoirs 😏 and was wondering what had become of Jeff. So sorry to hear that he is no longer with us.
Jeff built me two 6-string basses; a fretted one (based on a Ken Smith) in 1991 and a fretless (a modified version of the fretted) in 1995. As luck would have it, I only lived a few miles from Jeff and I visited him quite regularly; we discovered a shared childhood experience (at different times) in Chingford. I was studying with Joe Hubbard in those days and I got sneak previews of two basses which Jeff built for him (don't tell Joe).
I think Jeff used to ride a Harley-Davison? I heard a story where he flipped it after hitting a fox - not sure how true that was.
Although the fretless doesn't get too much use these days, it was invaluable during a couple of originals projects in the mid-90s and early 2000s.The fretted bass is still performing well. I'll sort out some photos.