i would ASSUME several things.
the notice of such a rise should be equal to the notice he would give if he wanted you out, or if you wanted out.
NO shorter. End of.
I would also assume that while its a bit inconvenient for you, he can do what the hell he likes, but if you think you can get a place elsewhere for less, up and move, and he MAY change his mind and realise he has been greedy.
If its to do with bills and him making enough money, then you shouldnt find anywhere cheaper anywhere else.
Iver never met, nor heard sight nor sound from our landlord, and the estate agents he goes through appear to not really give two tits whats going on, so until we need something off them (and struggle to get it) i’de like to keep it that way.