You could do worse than try emailing Clive Button who was the sole designer, from Series 6 on, TE bass amps/ combos and acoustic combos plus a host of other TE gear for the next 12 years from 1985
Bass - Series 6 range, SMX range, SMC range, 7 Band range, 12 Band range, GP7 Pre-Amp, GP12 Pre-Amp, AH150, AH200, AH300, AH350, AH500, AH1000-12, Valve Series, VA350, VA400, VR400, Twin, Quatra, Hexa, Commando range, Boxer range, PPA power amplifiers, Powered Sub 15, Bass effects pedal range, MP11 etc:
Acoustic - TA100R, TA50R, TA200R, TA Concert range, TA60, TA35, TA30, Acoustic Cube, TAB100 (Acoustic Bass), Acoustic PA 16 channel powered mixer system, Acoustic PA 12 channel powered mixer system, TAP1 acoustic pre-amp pedal, in fact everything that came out of Trace Elliot all the way through to 1997
I dont know whether he's still active, but i had an email chat with him some 8 or 9 years ago about my series 5 4x10 combo, but as he told me, he didnt design the series 5, but was helpful nonetheless
[email protected]