Probably phone numbers follow some numbering scheme etc. so it is relatively easy to spam everyone with automated dialing and handing the numbers that prove out to the scammer. Thus while it is possible sold by X, it is just as possible randomly pulled from limited pool of possible numbers.
Back in the good old days my mom worked for a short time for a marketing company making cold calls. Back when long distance phone rates were expensive the company would set up people locally and then just call every possible local number (eg. 678-XXXX). People with an unlisted number would get mad and ask where she found their number.
The fact that the call shows an origin number from UK does not mean that it actually comes from UK; source numbers can be spoofed in various ways, especially if it's not spam calls from legitimate companies but actual scam calls.