Aqua Panel around the bath and shower area

[SALL2009]

I need to install some aqua panel around my bath and shower area before tiling.
I’ll install aqua board from where the shower is installed all the way down to the bath. But what about the wall on the side of the bath. Would 3 foot high around the bath be enough and then use standard plasterboard on the rest of the walls?

 

[ChrisR]

I'd say it's not SO expensive to make it worth messing about with 2 materials on one wall.