It didn't inspire confidence when I had to explain to the customer services person on the other end of the phone what an Iban number and swift code were...
Call centre staff, for that is who you probably spoke to, wouldn't know what an IBAN number is as direct payments from overseas accounts are still not that common where private individuals are concerned.
I regularly have had to explain to a bank what I want to do and how they need to help me - I used to work for one of the big 4 but moved elsewhere 20 years ago to a job where my skills were better appreciated.
A possible solution is to use a trusted friend or family member in the UK who could send a cheque for you. Mind you many UK banks no longer issue cheque books.