my first thought was philadelphus, but if not scented......

it is stunning isn't it.

what about one of the Potentilla's is that a possible?

Leaves are wrong for the shrubby Potentillas. They have pine like leaves.
My first reaction was P. coronarius, but as I said, the lack of scent is confusing. The person who asked me about it, did say that he had a good sniff of the flowers.

#see Philadelphus inodorus

That fits the bill perfectly Stera. Clever you.

A lovely shrub, despite the lack of scent.

Distinct possibility. Thanks.