Thanks for all the replies folks. For me, it wasn't so much the fact that he was unavailable - I mean I have days where I'm unreachable all day - it was that there was an apparent lack of appreciation for my time an effort. I'm as understanding as the next guy, but the least they could have done was make a decent apology and maybe offer to pay for the mileage I put in.
As an update, I just had my interview with the Services manager a few hours ago. Despite pouring rain and heavy traffic I was 5 mins early. He was 45 mins late. But he did call at 08:30 to say that most of the roads in his area were flooded, so I'm not going to hold it against him too much.
The interview itself went well. I just hope they offer me a package worth considering. While waiting the 45 mins for him to arrive I happened to strike up a conversation with one of the technical guys there. From what he told me, it's not likely. But I'll cross the negotiation bridge when I get to it.
Again, thanks for all the replies. It's much appreciated.