Hello @John8923
I would contact customer support in this instance. Hosts are not allowed to ask for a deposit on Airbnb unless they go through a Channel Manager to collect the funds so this host may be in breach of the terms laid out by Airbnb.
Some countries do require guests to provide ID but like the deposit amount, this also has to be clearly explained on the listing. Is this the case John or is this a UK host asking?
If not, then you should have grounds to ask Airbnb to cancel this reservation and receive a full refund.
Let us know please how this is resolved,
All the best
Joëlle