I think 19th century? Not too sure of the exact dates. I do know that it persisted for a while after it was made illegal and then disappeared completely once it

I think 19th century? Not too sure of the exact dates. I do know that it persisted for a while after it was made illegal and then disappeared completely once it actually started being prosecuted. Vote buying could still re-emerge but it can only flourish in an environment where you can do it openly with impunity - i.e. it's legalized or the cops for some reason think they can't touch you. Your first link doesn't appear to be about vote buying (looks like low level postal fraud which is something else), the second is only about allegations (and again, postal fraud) and the third link looks like a 404 to me. I would be surprised if anybody's seriously attempted vote buying in the UK in the last 70 years.