Which mattress/ divan should we buy?

We are looking to purchase a new kingsize mattress/ divan with 2+2 drawers. We have only looked in Bensons for beds and liked both the iGel Pegasus and the Melbourne Divan. I've come across your website and wondered if you would be able to offer any advice. My husband is 5"11' and 11 1/2 stone and I am 5'3" and 9stone3lbs. We prefer a firmer bed. Both the ones we preferred have a firmness rating of 4.Are you able to advise if there is anything similar on your site? Budget is approx. £1,200 - £1,500.Many thanks