The whole "look at all these fradulent dead votes" thing rolled out by the Trumpy circles was (easily) shown to be very often a same-name-different-address issue where the actual voter was legit and not even anything to do with the dead potential-voter trawled up in a misguided global search (or, in one case, son-clearly-got-marked-down-under-father's-name). There's plenty of scope for some samenamedness to crop up, whether exploited deliberately or accidentally fallen into if you're determined to find such a case...
(The way it works over here, I think I'd have to be on the voter-roll as having the same name and address as someone else to stumble into my voting slip actually being associated with the information of someone else, unless the staff really mess up. I've seen how carefully they go through their process, though, as I roll up to vote, whether I'm in a slack time with no others having bothered them for a while or I've had to tag onto a rush-hour queue of dozens of others. I have actually read the "instructions for polling staff" documents, within the last few years (( for reasons I forget now, but I think it actually might have been for "what to do if the 'same person' turns up twice", as that's what I mostly remember learning most about )) and they're pretty much as thorough as I could expect short of actually requiring ID, which I still maintain seems not to invalidate UK elections by its absence.)