Wow! Is that in Surrey, Ginellie? Close-ups of the leaves and flowers might make it easier to identify, though trees that bloom that color in late winter in the UK can't be that common.

Yes, near Richmond Park. You are right about close ups being useful Tug but I just took in on my mobile so that's the best I could get. The blossom is highly scented if that helps. Someone also taking pics said she thought it was a Mimosa but the leaves didn't look right for that.

Is there naming confusion between mimosa & acacia here in Blighty?
Blooming spectacular though!☺

I would go for Mimosa (Acacia). Ginellie, your first thought might be right as there are many varieties with different leaves.

Thank you Darren and Jimmy. Spectacular is the word for it, and in such a small front garden.

Can't see it clearly but could it be a Mahonia?