Silver-washed Fritillary

With the warmer weather and open windows, we have a wide variety of insects flying into the conservatory.  Most we manage to rescue and return to the garden.  Sometimes ones that hid in corners are found lifeless in the morning.  

I think this is a male Silver-washed Fritillary as it has prominent streaks on its veins.  All this is new to me and comes from the Gem Guide to Butterflies and moths.