You can get Beatles singles quite easily both UK and US versions if you look around, it might be a little more expensive. However, it depends if you want original or re-releases. ( I am not a Beatles fan, so it's all the same to me)
Last year, a charity shop had a bunch of Beatles 45's. I bought the lot and sent them to a friend in Long Island. I didn't know I have sent a first pressing of MMT to him, it's worth a nice few quid.
Charity shops now use eBay and Discogs for guides, which is now annoying. If they see something listed they think that is what the record is worth. Not forgetting staff get first pickings.