My best advice would be ...if you're thinking about shopping at dreams ...don't!
Shop staff are excellent ...guarantee is totally worthless ...if you have an issue their " independent engineer" tells you one thing then reports back "no problem" ...so ....if you want a new bed ...buy a cheap comfortable one elsewhere and replace it four times in 8 years ...it's cheaper than buying their expensive beds and mattresses with a totally worthless 8 year guarantee