Replacing Silentnight mattress please help

Hi Very interesting site.

I'm just about to purchase a kingsize bed and - after deciding to spend (bur not yet purchased £700 on a handmade iron frame (the Victorian from nightsiniron.com) this leaves me with about £800 for the mattress I have tried out a few in local shops near me and the one that seemed to be best was the Albion from Marquis & Moore (Google it for details) ...

apparently that is exclusively supplied to one local chain (so in reality it is probably a white label from another company?) I can get this for a fraction over £800.

Just wondering your opinion and whether there are alternate options better for me.

I am around 14st and am torn between going for a medium or a firm ...

tbh up until now I have always had sub £500 mattresses (and am temporarily sleeping on a horrible Silentnight Miracoil 3) I sleep either on my back or my side - probably more on my side tbh Oh and just to add - as I turned detective after reading your site - Am almost certain that the Marquis & Moore Albion is made by Harrison (label is identical style and they use Postufil, Revollution and HD springs) >