Blacksheep,
Yes, it's very sad to recall the demise. Caused, I believe, by two main factors--the prevalence of multi-nation aircraft programmes where political necessity forced a third-party avionics choice, and the late take-up of advanced semi-conductor technology in the UK.
I know that Elliotts tried to make a run with some very advanced (!) 8-bit technology post-TSR2, but found no takers.
A side-comment on the dear old Mk.10 autopilot----on the Britannia, the main amplifier unit was positioned by the Nav's leg, far too accessible for those wannabe techies. Balancing the mag.amps was a true art, as I'm sure you remember, not a science, and I lost count of the number of times I had to re-balance the pitch channel after the Nav tried to correct some minor (usually imagined)porpoise-ing whilst in flight.
One even asked me once if it would help if he "tried changing to the other gearing links"...........
