I would be surprised if many Brits know of ARM as a British success story. Ditto for Raspberry Pi or Deepmind. These things are just not celebrated, it seems.
If you ask people in the street to name a famous living British technologist, they might come up with Tim Berners-Lee or James Dyson, but they are never going to name Sophie Wilson.
It is upsetting to me but you are right, they'd know Dyson. (I wish they would instead know the name Chris Duncan, the inventor of the Henry vacuum cleaner and while still a Brexiteer, a man who hasn't subsequently kicked dirt in the eye of the UK).
They wouldn't remember Tim Berners-Lee's actual name but they would be able to say, the web guy. (Which is probably better for him when he goes shopping).
But yes, few people who actually _build_ things, get to be famous public figures. Possibly due to being too busy to engage with the media nonsense or even worse social media nonsense.
Alas pjc50 specified living British technologists.
I mean, Britain has many great technologists if you're willing to count the likes of Arkwright (died 1792), Babbage (died 1871), Watt (died 1819), Faraday (died 1867), Randall (died 1984), Bell (died 1922), Harrison (died 1776), Logie Baird (died 1946), Stephenson (died 1848) etc
But some would say if a country's list of technology greats has so many dead people on it, perhaps that country's glory days are over.
£50 pound note, william churchill is the one on the £5 note.
This is burned into my brain. because I heard a joke when the redesign came out about him going from not being accepted by his country to not being accepted in Lidl. (£50 notes are often refused in the UK for fear of counterfeit.)