mcvj - coincidentally there is a CAB article in our local paper this week about this. The person moved into a privately-rented flat, landlord not paid mortgage, tenant worried about eviction without notice even though rent is up to date:
It says: "Until Oct 26th (2010) you could have been evicted by your landlord's mortgage lender without notice if your landlord was repossessed due to mortgage arrears, but you now have new protection. If your handlord falls behind with mortgage payments, the mortgage lender can go to court to get possession of the property. When the lender has possession they can usually evict anyone who is living there. However, new rules now mean that you can ask the court or the mortgage lender to delay possession of your home by up to two months, to give you time to find somewhere else to live." (This was in the Dover Express 2-12-10)
I hope this helps.