Unfortunately BT today struggle to preserve their operational line plant or even stuff from 1970s onwards; though there is plenty of it in private collections of their former engineers (including whole working telephone exchanges in peoples sheds :laugh_at:).
The early computer and networking technology was originally a civilian development to route telephone calls in London; both the concepts and hardware were widely reused in various parts of the UK for this purpose.
Loads of new tech was pioneered in the UK but we kept it shrouded in official secrecy (even though the original BT films from 1970s show some sophisticated piece of kit clearly being sold to the Soviet Union!) then Thatcho rushed to privatise BT so anything that didn’t provide immediate commercial gain was starved of investment in the 1980s.
They may still do occasional visits there but there really isn’t a lot to see now; the more interesting science lectures in the training halls have been stopped due to economic cutbacks and various bits of the building is now shared between BT, O2, Arqiva, Huawei, Cisco (and some others) and regularly visited by Home Office boffins (as its where the emergency service comms is designed) so its always at 110% paranoia mode.
In any case most telecoms equipment made since 1980s isn’t particularly interesting to look at – it looks just like anything else you would find in a comms rack anywhere in the world – and the lot of it is probably now maintained by about 3 overworked dudes with moustaches somewhere in Bangalore.
