I understand that even if Article 50 is instigated we still have until the end of the 23rd month to actual decide whether we’d leave or not
I’m not 100% that this is the case. It’s been mentioned in the press but while A50 doesn’t explicitly say we can’t change our mind, it doesnt say we can either? I think the option to withdraw from our withdrawal would need confirmation from the EU in some way before we trigger A50.
Logically, were there to be a second referendum, it would have to be once the full plan* was agreed to and then it would be ‘Should the UK leave the EU based on the proposal of xyz?’
I think its a pretty stupid idea though because about 20% of the voting populace would read the proposal, about 20% of that 20% would actually understand it, and the rest would vote based on whatever their particular favourite media suggests.
*EDIT – insofar as the plan can be full given the uncertainties