Deadline... 9th June!
If you've received all your decisions by 19th May, you need to reply by the 9th of June!
If you receive all your uni/college decisions by 19 May, you must reply to any offers by this Thursday (except if you are using Extra to find a place), otherwise, they’ll be declined. These reply deadlines are based on when you get the last decision from your university or college choices. Sign in to your application to see your personal deadline.
For further information and guidance, go to the following link https://www.ucas.com/undergraduate/after-you-apply/types-offer/replying-your-ucas-undergraduate-offers.