I often wonder about ours - they're just such slimey buggers. Just... Creepy and weasley, you know? They don't oversee any maintenance or anything, like I said they just pass on messages to the landlord, landlord sends someone, then we hear back again through the agent. They're glorified carrier pigeons, it's really ridiculous. They're a local company and appear to have somewhat of a monopoly over local private lets, so we've been dealing with them in our last two houses (the lovely village I live in now is only 6 miles up the road from the **** hole town I was in before).
Like you say, they haven't given any landlord contact information either time. There was a LOT of miscommunication with our last house. The landlord himself was in construction and gas etc. Certified so came round to sort things himself usually and was nothing but pleasant... And yet as I said earlier, after we moved out the situation with the deposit became quite nasty - I personally think because of the agency in the middle. I believe they pushed him to claim for little things that were just ridiculous. He was also annoyed that we hadn't told him about some damp on the bathroom ceiling, which we had reported to the agent multiple times and had even been noted down in an inspection. They then refused to give us the inspection details. We threatened them with a dubious data protection act claim and the next day one of their little gophers ran up to our door, shoved the inspection through, and ran away

. Supplied that to deposit protection and it saved us over £100 of our deposit. Landlord insisted that they had never passed on any of the messages regarding the ceiling.
I had a package delivered to the wrong address a few months ago and went to collect it, current tenants told me that the landlord had scrapped the agents and was just doing it himself this time. Which I must admit pleased me quite a bit. Utterly useless...