Is this mattress offer too good to be true?

[Purplekaz08]

Groupon are offering an Imperial 3500 Memory Foam and Pocket Sprung Mattress for £280 reduced from £999.
i am skeptical as usually is something seems too good to be true it usually is. However could really do with a new mattress.
i have googled the mattress and it seems to be made by Happy Beds, has anyone any experience of these mattresses, if so are they worth buying??

Following. Grouping I think tend to be reliable enough with their offers but it would be the mattress itself I would wonder about. I have no idea if that one is a good quality one.

www.amazon.co.uk/gp/aw/reviews/B00WOQGRRS/ref=cm_cr_arp_mb_paging_btm_2?ie=UTF8&pageNumber=2 reviews seem very good although one does state after 2 months natress was in bad shape. Seems a very good price compared to other places

Not sure if this is any help but the DC's bunk beds and mattresses were from Happy Beds and we've been very pleased with the quality.