Was sent a Silentnight Eco Comfort Miracoil Mattress as an "upgraded" replacement for mattress that sagged after only 20 months. It's been rotated every week, but after only 19 days this mattress is also sagging. Response from warranty dept " 1st impressions are as though the mattress has been sat on extensively". It's not been,but Silentnight would appear to believe 19 days is a long period of time. After several emails was offered another "upgraded" replacement,checked reviews to find if anyone had similar problems with this one sagging and they had. So my options are--- like for like replacement-another "upgraded" replacement -both would mean taking the risk of having to go through all this again-or the £48.00 I payed for delivery . I would advise anyone to think very carefully before buying a mattress from Silentnight.