In the meantime, I used the rolling mill to take the thickness down, and just used shears on the resulting pieces, then hammered and shaped by which time they were nice and stiff again (last thing you want is to put enamel on a flexible piece of metal as it will just crack off)
I enamelled the smaller squares by holding them at the very edge and just managed but I think I'll either make a hole in the middle in future or work out some sort of tripod and mesh affair to heat them on.
The edge of the pink on one of the pieces cracked a bit as it was quite a thick area of glass but I reheated, pulled off a bit of glass and flame annealed more carefully so we'll see if it has solved it.
The headpins are just an ongoing challenge, for some reason they are one of the more difficult things to get the glass to stay stuck to! I made four, only two have survived to the photo and who knows if any make it through the night :-)