Much as I enjoyed it (lots!), I agree with roscoff about the old-school friends being non-characters. Katy Wix and Sally Phillips are both great actresses but their characters here have little (no!) depth.
Admittedly, I would have blasted this fact if I was critiquing it as a script. Same with the coincidences being a bit far-fetched. However, I was having such a good time watching every episode, that I forgave both of these facts. All this proves is that if it's funny, you can get away with other 'vital' sitcom-writing aspects. Certainly to me and (dare I say) the majority posting, but evidently not to other people.
Maybe the second series could do with fleshing out these characters and getting rid of the all-too-coincidental coincidences, but not if that's at the expense of all the fun.
The end credits bit is great fun. Love it! Keep it!
Dan