overpayment of home insurance


I have been in ill health since 1995 when I had 3 strokes and in later years 2 heart attacks I have had a home insurance policy from pearl which in 2007 its liabilities were taken over by lloyds. The original policy I signed for stated that I lived in a 3 bedroom semi detached house built in 1957.
When I got the letter for my first annual renewal of the cover I read it and so did my wife and she says she can remember the policy schedule stated 3 bedroomed semi detached house the next annual renewal we read that as well and it was the same. So the later renewals as the strokes had left me with memory and concentration problems all I would read was the following paragraph in the polcies ' if you're happy with the enclosed policys and if you already pay by direct debit you dont need to do anything we'll collect your premium as usual on ther due date' but I am a bit better now and I read this last renewal and policy schedule and was amazed to find they had me down as living in a 6 bedroom semi detached house and when I phoned them even more amazed to find out that they had it down as being built in 1836. The girl I spoke to reduced my annual payment by about 300 pounds for the current renewal. Iasked what about the excess payments she said they could only offer me 11.00 for the current year I asked to speak to someone more senior she said she would get someone to phone me back that afternoon no one did. I have taken legal advice and been told to write them a letter delivered recorded delivery and await there response. I would just like to know if I will have any sort of case I admit I did not read all the schedules but I just thought they would be the same as the first ones. Somewhere along the line a mistake has been made changing the number of bedrooms and date built. Its not been a mistake on my part though.