I agree the provision in our area is shocking. I don't know what DH would have done if he'd spent this last week alone and completely without support.
I think, being honest, he's out of crisis. He's still fundamentally depressed and that's not something that's going to change in a hurry (if ever), but he's but back to his usual methods of coping with it, in a sort of plodding "oh well, life is mostly shit" mentality.
He's up and about and fairly "normal", which he was miles away from last week. I don't think it's an act, though I'm aware it could be, I'm usually hyperaware of those even if I can't get to what's behind them.
We've talked about the NHS counselling which apparently might turn up in a few months since he's been on the waiting list since last September, and I've said it could be very very crap service. He says he knows but he wants to approach this in his own way, I think that's important to him.
Potato, thanks so much for posting, and while I'm sorry to hear you've been through the same sort of thing, it's vaguely reassuring (if that's the right word?) to hear we've not been alone in our experiences. 
I'll google Rethink this morning. I guess if we hit that extreme low again we'll know what to expect from support services. I hope your DH is doing well?
I have to go back to work in the next few days; I'm going to go in today to see my boss and catch up I think. I hope dh is okay being alone again so much. I purposefully went to the shop for half an hour yesterday, which was hard.
Thank you again everyone for replying. When my brain feels less numb I'll feel shit for not responding one by one but right now just thank you, I appreciate it.