Noptes on the Vi Spring - the base comes in two halves and is bolted together, it can be one piece but they reccommend two, likewise the mattress, it is easier and safer to turn two, though they are still heavy!
Fitted sheets, as the matresses are so deep, I get mine from Debenhams, the Sheridan Range, plain 100% cotton and called deep fit. They also do poly cotton if you prefer.
I had a lot of bed linen made, it was really cheap, all 100% egyptian cotton by a firm called the Finishing Touch direct from the mill, I think they were in Derbyshire, I found them in the factory guide and called them. They were so helpful, sending cotton fabric samples, and they delivered quickly. They will make every thing to order, mattress covers too. It is only the same price as JLP or Marks.
Some of you have had good bargains, we've got the one next to the top of the range, Tiara Supreme
I wish we'd bought our bed in the sale, mind you we did get a good price, it was £5700 in John Lewis, but a local firm specialises in Vi Spring but are not allowed to advertise that they undercut. We paid £3000 for our about 18 months ago. It is brilliant!