Another CGT question

[soapbox]

I want to make a gift of some assets I am disposing to my wife to use her PA. I think I remember from my days in practice that you needed to complete some kind of deed of assignment, which was basically a letter confirming what was being gifted and the value.

Does anyone know if this is still the case (to satisfy HMRC) or have they come up with a form I need to complete?

Thanks