Madwoman regarding your post wondering about why the girls value their girl-only space, I think it is because they feel freer to be who they are there.
I've been a guide guider for many years. At my first unit, when I was at uni, the unit was full of the most non-stereotypical guides that you can imagine: streetwise, 'cool' and rebellious. They loved it. It was because they didn't have the pressure of looking cool for the boys, they were altogether doing a range of activities with confidence.
When we took them to a Guiding campsite, they gave up hair straighteners in favour of French plaits and pigtails (their choice) and lost the make up. They acted like their age (10-14) and not like mini-wannabe adults. It was wonderful to see. However, on their final morning, the plaits came out, the make up went on and the tough mask went up.
Now I do guides in a totally different area with more of your 'traditional' type of guides. We took them camping at a shared guide and scout campsite last year. As soon as boys arrived at the neighbouring field, the behaviour of the eldest guides changed immediately. They became obsessed with trying to see them, became extremely giggly and more reluctant to do the sort of activities they enjoyed the previous day.
I agree with our single-sex status. Our waiting lists are massive, with a large number of girls having to skip Rainbows because of the waiting list, despite being on it since they were three and despite there being 4 units.
We'd open more if we could get more leaders. As it is, pretty much every leader runs at least two sections! Same with scouts. You want places, you need to volunteer.
I have a DS and am already planning to volunteer once he gets to age to ensure that he gets a place.