Absolutely, the run lasted until the mid XXth century.

(Although some of the stuff you list as "great firsts" didn't turn out quite as amazing as all that or was much better done elsewhere)

After that, not so much. I can only think of graphene, a discovery rather than an actual implementation (and which, by the way, has yet to produce actual practical results anywhere close to matching the grandiose announcement of how groundbreaking a discovery it was).

For a country of 60 million people with all the wealth and institutions it still has left of from the age of Empire, Britain has been punching below its weight since maybe the late 70s or early 80s.

As I said, modern Britain isn't a country of doers, it's a country of talkers (a subsection of whom seems specialized in relentelessly celebrating past glories) or at least a country that rewards tall stories and swindling your fellow man far beyond merit in execution and the direction of travel seems to remain a worsenning of things in that regard.

It's thus not surprising to see a story like this selling this Great British Achievement (tm) which turns out to be a plan to start work on planning it and is clearly a play for getting more funding.