We also had workers, builders of any sort coming with no notice and using the keys provided by the agency without even knocking (once early int he morning when I was on my own, sleeping!!). It was happening almost every week for several months! I also had to clean after them.
We were also forced to steam clean the carpets even though they hadn't been steam cleaned before we moved in. We thought we had to but another agent told us we didn't have to even if it was in the contract.
Other common lies/tricks like: the house will be professionally cleaned before you move in, the internet connection is in progress and will work next week, that will be fixed, we'll bring tv/washing machine,etc - NEVER believe that, it won't happen.
And another thing: all those agents who lied to me, tried to do some nasty tricks, etc. Are they really that stupid the don't realise that I am a potential house buyer and that I will avoid their agency like the plague ? Not just the agency - I will remember those agents' names and/or faces, I will warn all my friends against letting, leasing and buying from them. Pretty obvious thing, is tricking me to pay some extra money at the end of the lease really worth it? Not to mention such things as human or work ethics... Also, can't they appreciate good tenants? Clean house, tidy garden, no noise, no complaints from us or others. We even watered the garden after we moved out because it was supposed to be hot and the landlord was not back yet. And we offered it because the agent was a decent person and we both truly cared about the property. But it was one agent out of four - so far.