What shrub is this?

Hello
My son has been doing work experience at a retired botanic garden in Wiltshire. This beautiful flowering shrub is thriving in this week’s warm weather but nobody seems to be able to identify it. Any suggestions as to what it is? thank you

 

Google lens says it's Berberis valdiviana. But the foliage doesn't look as shiny as Berberis - also not sure of the scale - a hand in shot would help please!
It looks great though.

 

I agree with @CarolineL foliage is not right for B valdivana I have that in my garden.
A couple of questions roughly how tall is the shrub and are there any spines on it?