I can't provide a concrete answer but I've seen 16 weeks quoted. But looking at the build date thread for the Leons it looks like even this might be too short.
I'm in the same situation regarding the Nationwide offer. I took that offer because they quoted January delivery. I see the same advert is now quoting March delivery.
They claimed that they were guided by the
dealer but If they're aware of such massive delays they shouldn't be quoting any dates.
Their T&Cs say you lose the full admin fee at this stage. But to me, their advert was misleading. Not all their adverts show delivery dates so by having one, it implies the car at least has a build date.
For them to then come back and say it doesn't, seems dodgy to me.
What's to stop them taking your money and not delivering anything for a year.
There are some other guys on Pistonheads who also have the same issue. We all took the offer because of the stated date.
I don't suppose you have a screenshot of the original advert showing the date?
I can extend my current lease for 6 months but I don't know if even that will be enough.
If I cancelled it might be a fight to get the admin fee back. But as far as I'm concerned it was false advertising and they haven't fulfilled their side of the contract.
Need to ask the question on some kind of legal forum I think.