Are there any examples from modern times of the result of a UK election, referendum, etc., not being implemented, or the question being put a second time (perhaps in modified form) before the first result was implemented? (Whether or not that second vote went the same way.)
Not including things like a by-election because the elected MP died before taking office or similar "acts of God" as insurance contracts used to put it, and not including hung Parliaments.
I mean things like: There was a substantial delay, and/or significant implementation issues, and/or there was a change of government, and the result was either just never implemented or eventually the government brought the question or a very similar question again (whether or not that subsequent vote went the same way).
Here's an example that would be what I'm looking for except for one thing: In 1978 the UK government passed the Scotland Act which would devolve some powers from Westminster to a Scottish Assembly if a referendum passed. The 1979 Scottish Devolution Referendum was held and the result was 51.6% "yes" to 48% "no" — but the Act wasn't implemented. It wasn't until 1997, after another referendum and another Act of Parliament that the Scottish Parliament and Executive were created.
Why isn't that what I'm looking for? Because I left out a bit: The 1978 Act included a provision (an amendment) that not only did a majority of those voting have to vote "yes," but those voting "yes" had to be 40% or more of the total electorate. This requirement was known prior to the referendum. Turnout was 64%, so the "yes" vote was 32.9% of the total electorate, short of the Act's required 40%, and so the result wasn't implemented. (Famously, there were issues with the electoral register [dead people still listed, etc.], but that's not relevant here.) If it weren't for that 40% amendment, it would be exactly what I'm talking about, but the 40% amendment was known beforehand, so it isn't.
(Yes, the inspiration for the question is Brexit and calls for a People's Vote / confirmatory referendum / etc., but Brexit is not the topic. The topic is results that were not implemented [or not prior to the question being put again].)