Well, looks like we might have found the right counsellor - at least, the one we saw on Wedesday seemed much more professional, more perceptive, and very positive. DP said afterwards that it felt like a quite different experience with her. This morning I said, well, shall we continue with her? He said initially, let's talk about it tonight (having said the same thing yesterday, and we didn't) - and I said, look, it's Friday, if we want to see her next week, we need to book the appointment today. He then said, she seemed overly keen! 
and I said, Darling, you will find something wrong with EVERYONE - we both liked her, why don't we try a few sessions and see - and maybe she was keen, because she could see we needed help! So he laughed and said ok, book it - and I have. She certainly seemed to pick up well on some of the points that came up, and agreed that at some point, it would be useful to bring DD into the meetings. She said it seems that DP has low self-esteem and a self-destructive pattern that comes into play every time he's happy, that DD maybe triggers something from his past, and that I probably have had several relationships with people with low self-esteem, because I am a natural 'rescuer'. All true! She also said that we are a glass half full and glass half empty couple, and that's why we're together. We laughed at that. She also commented that we seem very caring of each other, so it's worth working through what's gone wrong. Not bad for an hour and if that was being overly keen, I found it a very uplifting kind of keen. If she doesn't work out, I will try the teenage specialist guy, though it looks like he's based outside London, judging by what I've googled on him.
The only thing is - DP really does need to address the drinking. And I really wonder if he's ready to. I don't think any amount of therapy will be effective long term, unless he does. Anyhoo, watch this space.
Hope everyone else is ok and keeping warm.