You are paying for a new ref report based on their combined income instead of just his. If you needed a new report based on 5 adults it would also be the cost of 1 referencing report
if he cant afford on his own and didn’t tell you in first place that tenancy would include his wife and it was their.combined income paying the rent, so you needed to reference the two of them together it’s a bit sloppy on his part isn’t it?
You can’t charge tenant the 30 quid due to tenancy fees act but if you are keen on this potential tenant, do the referencing again but ask if anyone else will be on the tenancy inc any permitted occupiers (such as children or other adults ). Ask if he can add a guarantor too.
Or just move on and find someone else who’s better at comms and passes the referencing 1st time instead of wasting your time
Join a LL association and do the training- it’s an allowable tax expense.