I'm fairly sure it would be the TM. The First Class hosts on XC are generally very good. However, they do seem to be short of them. Which would explain there not being one. Generally the trolley comes through instead, but that can take some time.
Once I had a host who was very good, seen a few times. Then at New Street a couple of men in suits (with an XC shirt and tie) and an XC name badge that said something like "Revenue Protection" got on, had a word with him, one got off with him, the other remained on and served First Class. Never saw the host again! Having used that service many times before and since, I know that there is not a booked host change there