First things first Simon, beautiful photo, love the delicate majenta's of the flower, but as an acknowledged expert on lepidoptary I would suggest that you have named the species inacurately.

The silverstudded has a very obvious dark fringing on the upper wings, my photo of this butterfly shows no fringing at all, changing abruptly from blue to the white feathering. My guess is that it's an Idas Blue.

Of course take everything I say with  a pinch of salt, apart from my first statement.

Harry,

What made you think I would make pictures of the same butterfly as you???

Now I thought this was an Idas Blue, but...........

I have since looked it up and am now fully confused. (didn't take much)

Apparently the only way to find the difference between a silver studded and an idas is that the latter has a spine missing from its forelegs. Now start counting these spines

It was a good day shooting though.