Hi James,
I echo Ethel's' comments, buying a decent bed is worse than buying a car. You have to spend at least a third of your life sleeping and if you have a bad bed you are asking for trouble.
We spent over �1000 just on the mattress alone, that was a VI Spring, it came with a 30 days trial period but we found the bed so comfortable we decided to keep it. I believe it was money well invested as I am sure that it will last for a few years.
The actual bed itself is a wooden slatted Boxer from John Lewis, this has made a big difference to our comfort.
The choice must be yours and nobody else's.
Regards