@ djinn,
your friend paid the deposit to an agent and not the landlord...so any issues to do with money,he would have to get the agents,not the landlord
as for the repairs and additionals,your friend entered into a verbal agreement (which is not binding) with the landlord who is not tied by any tenancy-landlord agreements...the letter of offer here is meaningless as it does not constitute an agreement...
so in this case i see two scenarios.....
firstly,your friend is offered a house,pays a deposit for it and agrees to occupy it a month later but does not occupy it...he is theoretically already in rent arrears in as far as the landlord is concerned...the landlord has the right to sue him for this.
your friend is not due for any refund in as far as the agent (receipt issuer) is concerned because this deposit is meant to offset the cost of minor repairs in the rental when the tenant is moving out and the defaulted rent....so the agent can also sue him for rent default....
either way your friend is not safe unless of course he is dealing with an 'understanding' landlord......
NEVER TALK OF A RHINO IF THERE IS NO TREE NEAREBY - ZULU PROVERB
...besides, the presence of a safe alone does not signify that there is money inside...