Hi got planning permission in 2002 for 2 storey extension and had the ground works checked but not the inside, did not realise this at the time of putting the house on the market as my husband dealt with all of this type of thing and he passed away at the end of last year, if my buyers had not told me I would be none the wiser, does this mean they could pull out of the sale, the extension has been up for 10 years. Help!!