Have namechanged for this
I used to work at my company and left. When I worked the first time I had a long notice period (6 months). 2 years later they offered me another role and I came back with a 3 months notice period. They then promoted me and I got an offer letter but no new contract and in the offer letter, it mentioned no changes to the contract other than what was in the offer letter. In the interview for the promotion, they mentioned they would move my notice period back to 6 months but that wasn't in the offer letter. I pointed this out to them but they never bothered to correct it.
I've now worked there for another few years. I have now resigned and given my last day as 3 months away as per my notice period in my contract. I have another role (though they don't know that) and it starts in 3 months time.
Work have gone absolutely mental and said no way can I quote a 3 months notice period and that I knew it was 6 months and I'm being 'morally bankrupt'. I said it's what is in my contract.
Obviously I don't want to burn bridges but the last 12 months have been hell there (change in management and it's just been dreadful) and if I could leave tomorrow I would.
I don't think they can try and say I have 6 months if it's not written even if that was the intention?