Fitting a windscreen, any tips?

[Ratty]

The screen in my 63 is starting to de-laminate in places and though I was going to just live with it due to the costs of replacement (Getting on for $1000 by the time its shipped to the UK), but I've just been offered a good used one for a measily £50 ($80ish) locally so it looks like a swap is on the cards.

What I'd like to do is fit the better used screen but also remove the one thats in it now in one piece to save as a spare. So, any tips on removal/fitting a wrap-around screen without breaking it?

Ratty