Signed McCartney CD

Hi All,

I’ve got a CD signed by McCartney - the number 1’s CD. I met him maybe 13 years ago (my memory is awful), at the Garage in Holloway - he was there with Stella and was watching her nephews band play. He said the record company didn’t really like him signing stuff, but signed it anyway.
Now I’ve tried selling it on eBay, but they take the listing down every time, since I don’t have a CoA. I was wondering if anyone could help me with getting it authenticated - like who may be able to do it. I’d like to sell it, as I’m looking to save money.

Thanks in advance.