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This turned out to be weirder than you could imagine! It was an heir finding company but it wasn't about his father's estate.
Thanks for the advice on not signing jackthehat, small print included having to appoint their solicitor for a minimum fee of £500!
Thanks for the link dzug2 contacted them directly and found everything out.
Here's the weird part.....
He had a badly disabled son with his late wife and as they were young, with two other children, by the time he was about 5 they were struggling to cope. He used to go into a care home to give them respite from time to time and an older couple who used to visit all the children there fell in love with him and asked if they could adopt him. Although worried about this couple's age, as their son only had a short life expectancy, they didn't think that he would outlive them and they decided that this couple could probably give him a far better life than they could. They clearly doted on the boy so eventually they agreed. His wife got cold feet at the last minute and didn't sign the adoption papers although he did go to live with the couple and they became his guardians. They still used to visit him from time to time with the other children, but not so often that they were a nuisance or a confusion to the boy. (cont)