I was never a big buyer of singles and only have a few now. I do wish I'd kept the little collection of 45s I had that had belonged to my mum. Those might be worth a few quid. A nice cover was a bonus and who doesn't love some sleeve notes? A lot of my LPs are re-issues and so probably not worth much. I have no idea of the state of the collector market. Some of my CDs may be limited editions and I do prefer the card ones to the ultra-fragile 'jewel cases'.
I don't bother hunting down stuff to download these days. I can get just about anything on Spotify or Youtube. It's fairly easy to extract the audio if you want it. Getting the cover art may be trickier. Is there are big database online of them? Seems the sort of thing someone would do.
There are plenty of images.. eg see below.
..but which ones is the UK release? If you once owned it, then it will be in the deepest recesses of your memory, if you had the non-cover version then it's a litte trickier to work it out. Singles had an ID stamped on them, and you can sometimes figure it out from this.
Looks like Discogs and ebay are good for this. It's interesting how many different covers there were. Must keep the collectors busy getting them all.