Hi, I would say it's a Deutzia, possibly D x magnifica 'staphyleoides', Derek.

could it be one of the Amelanchier species. they are in flower now and the leaves are more like this than the Deutzia I used to have.

Thanks for your replies. I do believe it is more likely to be a Deutzia as I recognise that name and not Amelanchier, and it would be more like me to buy something I had already heard of. :-)

No, not Amelanchier, and the flowers do look like Deutzia . . . does magnifica grow this tall(?) but it's very pretty!

Hi, D x magnifica 'staphyloides' grows to about 10 ft tall with a spread of about 6ft, Derek.

I've kept looking at this and yes, the leaves do look like Amelanchier but to my recollection, the flowers on Amelanchier appear before the leaves so you wouldn't have mature leaves and flowers at the same time. Therefore it muct be a variety of Deutzia.