For nano sims, will an Apple Store copy over sim details from micro sim to nano sim so I can use my preferred network provider?

Looking to get a sim free iPhone 5 when they are released, however, I am on Giffgaff in the UK and they won't be having nano sims for a little while yet.

I heard that when the iPhone 4 came out, the Apple stores were able to provide non-branded/apple branded microsims and port/copy the details over from the normal sim to the microsim and away you went.

Is this correct? And if so, will they be offering the service for micro - nano sims?

I'd like to stay with Giffgaff and don't fancy messing around with my sim!

Cheers

Karl