Tenant unable to pay

I have two tenants who were meant to move in on 1st September (4 days time) and now they tell me they can’t access their bank account.

They have paid the holding deposit and signed the contract.

My question is:

Do I just receive the holding deposit if they fail to pay and move in, or am I entitled to more e.g. the first month’s rent for breach of contract?

I would have thought that if they have signed the contract then they are legally obliged to honour it in full unless you mutually agree not to. The most reasonable thing is to get them to agree to pay for the first month to give you time to get a new tenant, but reduce it if you get someone sooner.