Which mattress?

Excellent website I have an existing bed frame and i need to replace the divan and mattress on it. It's a funny size - 5foot6 inches - so i can't buy something off the shelf. I would like to invest in the best pocket sprung i can get for around £3000 including the divan. What should i get. I tried out some great Spinks ones in John Lewis which gave me a taste for quality but you seem to suggest i should go off the high st. Can i do this if i need a special order?

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