Above average. It was certainly better than good, but as many have remarked - a lot of it was setup. I liked the slow build up, personally.
You have to wonder why the Beeb can't just let these things run an hour if they need to (which they do occasionally). I suppose you have to pick your battles. I can't think of many other BBC shows with a 45 minute running time. Can anyone?
Must be to sell the show abroad (ie with adverts?). Thats the only reason I can think of.