Hi Megson, thanks for your reply - the recommendations are much appreciated! - and I'm sorry about the long delay in responding. I've put Mostly Autumn's and Karnataka's samples on my downloads queue but I still haven't had time to get them yet. Will be back in a week or two when I've had a listen.
I've not heard any of Máire Brennan's recent music but I'll be interested to look at that too. Her voice is gorgeous but I'd lost interest in the music she was doing with Clannad quite a while ago, and haven't heard any of her solo stuff. Clannad's early trad folk and crossover albums were their best work for me... after they went further over to new age/Celtic pop, round the late 80s, I lost interest.
I'm a bit gobsmacked by your comment about finally becoming a fan of the female vocalist!! I've always liked both male and female singers. There's such an incredible range of female voices that it's hard to see how none of them could be appealing.

But anyway it's good to hear that you're finally coming around to liking some of them.