I've recently purchased a complete surround set with a gas fire.

It's a similar sort of deisgn as seen on the B&Q website -

http://www.diy.com/diy/jsp/bq/produc...95&paintCatId=

My question is what would you recommend for securing the micro marble
surround onto the wall (plaster)?

The hearth is all level and the surround is ready to sit on top and
secured.

I popped to B&Q yesterday and asked what they recommend. He suggested
using dabs of Fireproof cement on the back of the surround and then
'stick' to the wall. However, although it will do the job, I'm not so
sure. It will make it difficult to remove if I wanted to in the future.

Will no-nails suffice?

I need to get the hearth and marble surround fixed before a corgi gas
man can come and connect up the gas fire.

Look forward to your replies.

Many thanks