Strangely, I got a letter from revenue about a year into letting telling me that any refunds from revenue would be automatically refunded to the same account in which they paid their rent into. I had not given revenue details of this account so I presume they just sent me this to clarify that I was their landlord and that they were paying rent. (I had given my PPS number from the start). So I guess if you pay rent into a bank account your LL will know. I have to say, you are entitled to the relief so you should claim. If you're shielding a friend from the tax man you need to examine your conscience. I apologize in advance if I'm way off the mark here.