1. NO, the hotel can not prevent your guests having access to the hotel up till 11am on the Saturday morning. Essentially, where a contract has been made for a wedding to use a hotel's facilities and for guests of the wedding party to stay there, it is a breach of that contract for the hotel to unilaterally seek to breach that contract and impose terms of their own. Accordingly, I would advise your daughter and her wedding party to stand their ground. By law, a hotel is obliged to honour all bookings made and to compensate for any bookings which are not honoured. Failing to allow access to the hotel at set times is also a breach of the condition that a hotel honour its bookings. It cannot simply seek to prevent guests enjoying their stay. So the hotel are in the wrong in legal terms here.
Thankyou for your advice, it was very helpful. The letter, of which I have a copy, has now been withdrawn.The wedding service and reception went exceptionally well and was enjoyed by everyone. A day to remember