If I’m looking to buy a product, I’m more likely to click through on a .uk domain of some sort, because I’m then pretty sure it is a UK site. (It’s frustrating to find what you want on a .com, then discover it’s not available here.) If I’m looking purely for information, then I don’t care particularly.
As far as search engines go, as I keep telling you, they are concerned primarily with whether or not the content of the site matches the search query. The domain name - and particularly the extension - will make little difference. If you want to target a UK audience with a generic TLD like .com, you can set the geographical target for Google in Search Console.
If I start with a .com, build backlinks and then want to change to .me.uk would the backlinks count towards the .me.uk if I do a 301 permanent redirect on the .com to the .me.uk?