1. Who is named in your contract as the client/customer/booker/promoter (whatever you refer to them as in your contract T&Cs)?
Do you have a clause in your contract that the person signing the contract has the full authority of the client/customer/booker/promoter to enter into a contract on their behalf?
Legally, believe it or not, a contract does not have to be signed by the person entering into the contract. It can be signed by anyone - so long as they have the authority to do so on behalf of the person to be bound by it's terms.
In practical terms, it's always a good idea to get the person indicated as your client to sign, so that there can be no argument afterwards, or, failing that, at least an email or some such confirming that the person who signs has authority to do so on behalf of the client.
Let's assume for the minute that your contract indicates that the bride is your client: TBH, the bride would be hard pushed to argue that the father of the bride did not have the authority to sign on her behalf in these circumstances, but to cover yourself, why not just send an email acknowledging receipt and saying that you note that the contract is signed by her father and assume (unless you hear to the contrary) that he was signing with her full knowledge and permission.
The other alternative would be to insert the name of the bride's father as your client, but to make an alteration at this stage, you would need permission (ie you can't just change it unilaterally an call it a binding contract!)
2. Again, what do your T&Cs say? At what point is a legally binding contract formed? Ours state that in order to have a legally binding contract, we must have the deposit and signed contract.
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It's a bit difficult to give specific advice on documents without seeing the documents themselves, but I hope the general advice above is of some help