The office does have a land line, but the lab I tend to work in doesn't so there didn't seem a lot of point in giving the estate agent the number.
I think the point about being a bit ambiguous is probably valid, so will have a polite conversation on Monday with him and express my displeasure at him randomly turning up. Like someone said, even leaving an answerphone message for me to collect later would be better than making no effort at all.
If he'd done it during the week, I probably wouldn't have as much of a problem as I would be at work (as far as he knew) but I could have potentially been in on a weekend, and that could have caused an awkward situation if he'd just turned up without letting me know.
I have been leaving the house spotless, but after another argument with the ex, I was in a foul mood, and needed to go out and do something, and as I hadn't heard anything from the agent decided that leaving the place in a mess wasn't going to be a big issue.