Mick Hawksworth - what a nice man. Yes that Thunderbird has indeed got a new centre block. It was actually owned by Gary Thain (Uriah Heep), and Mick bought it (with new centre block added) from the guy who inherited Garys equipment.
His current band is called Tres Geezers and i'm going to see them in a couple weeks (Surrey somewhere if any UK readers fancy a night out). He plays de-fretted RD Artists these days. There will be plenty more in the interview when I finally get it done (you all know what i'm like, it'll take me some time) but for now check out his bass playing on these tracks from the 1971 fuzzy duck album. Nice.
Check out the breakdown from 3:20 - why hasn't someone sampled that?