I'm with Martin & Co too,
2 weeks ago the same thing happened to me, though I don't think I can prove it. My girlfriend got a text at 5pm one day 'reminding' us of an inspection the following day (I wasn't contacted, even though I'm the lead tenant). I told her to phone them in the morning and let them know that they're required to give 24 hours notice and that they weren't welcome to do the inspection. She did this and they said it was fine, they'd re-arrange. They haven't re-arranged and I suspect they came round anyway, because the door was locked differently that day (gf actually couldn't get in - she sat outside waiting for me to get home to unlock the door as its dodgy sometimes - this time I guess it was particularly stiff because they managed to lock it differently somehow).
We've had all sorts of issues with them regarding lack of contact. Before we moved in we put as a condition of our tenancy that there should be a freezer installed as there wasn't one already and we'd be bringing frozen food. Despite many assurances that there had been one put in was there one there on moving day? was there ****. The landlord actually had to do it himself in the end. And he lives in abu dhabi!
It's easier to talk to them face to face by walking into their offices because they will never call you back. Even then we've been given excuses to send us away at the office like "oh the printer isn't working" (when asking for a copy of a document) and "so and so isn't here right now, i'll make a note" etc.
Now that we're in, we're in.. but I'm dreading anything going wrong or moving out because we'll have to deal with them again.. At least here in Scotland our deposit is protected etc.
5UB, just do everything by the book. record contact, get copies of what you need, get them to sign things. Their word isn't worth anything as I'm sure you know.