I think that maybe Sylvia has hit the nail on the head. I've found the following explanation of what the certificate relates too.............

Certificate of acknowledgment of a deed by a married woman
These parchment certificates can sometimes be found attached to conveyances, or occasionally on their own, having become detached from the relevant deed.
The earliest certificates date from 1833. They were brought in thanks to a clause in the Fines and Recoveries Act of that year. A married woman selling or mortgaging property jointly with her husband had to be interviewed separately by a public official to certify that she was 'of full age and competent understanding', to confirm that she was not being forced into agreeing to the sale.
The background to this procedure was that any land or property owned by a woman became the property of her husband on their marriage. Therefore, if she had inherited a house from her parents, her husband could sell it. However, under common law she was required to be a party to the deed. The acknowledgments represented an attempt to prevent husbands from abusing their position as owners of property which had come to them through their wives.
The Married Women's Property Act of 1882 gave married women the same rights over their own property as single or widowed women, and did away with the need for acknowledgments.
Purpose
Confirmation that a married woman was fully consenting to the sale of property.

Unfortunately, only a viewing of the document file is going to give any further information. However, Abel Wood WATKINS was a farmer as well as the "Keeper of the Prison". He is identified as such on several baptism certificates of his children in 1824 and again on the marriage record of Susannah and GEORGE HALFORD IN 1846 at Parkend Chapel. It seems logical that he may have bought, sold or rented land during this period. Abel Wood would have been abt. 65 when the document was dated so it could be that he had decided to retire from farm work and was selling all the assets with his wife's consent. He died in 1848 at St.Briavels so it looks as though a 'will' could also be helpful.

It seems as though a visit to the Gloucestershire Archives may be the only way froward in order to find out anything more definite. Unfortunately I live abroad so this may have to wait until my next visit home.

Sorry Sylvia, but your GWILLIAM and POWELL connections don't tie in to my WATKINS tree at the moment. I'll be aware of them from now on just in case the names appear in relation to any other members of the family.

Thanks to everybody for getting the grey matter working again! It's much appreciated.
Allyn.