Paula,
I would try Peter Best Insurance , ask for Julia Richardson and tell her you are a friend of mine for a quote and valuation. Tel Number is 01621 854485
I've put all my insurance through them and they are very, very competitive . I'd try for a £20k valuation. If we all go for the same sort of valuation, someone will start to listen..mine would cost more than £25k to replace anyway...
Kindest regards,
Richard
R.M. Fairclough