My daughter had the best experience at Wincol and said "it was two best years of my life". She is missing the college so much now at her first year at uni. In her (boy's house) all girls formed very strong friendship and see each other and boys from their house and other houses in London (as they are in different unies, including abroad). They all used to hang around in Winchester on Saturdays and now go to London clubs together. The boarding house leavers trip was a very positive experience for most.
Now, there are some inter-uni visits too. Moreover, at my ds' uni, OWs keeping together (herself and 2-3 boys).
I've heard from other girls from Wincol that same line "best experience of my life".
To be honest, at the very beginning there were some initial hiccups as it was the first year when the boarding house my daughter was in accepted girls. Not all boy's parents (and some boys) were particularly impressed. Also, some boys just didn't have enough experience of communicating with girls and were a bit scared initially.
However, most girls came from mixed schools and were quite familiar with handling boys and setting boundaries where needed. At least with my daughter, she came out of the school strong and confident, knowing how get around (sometimes) toxic male environment. It will definitely help her if she will go on with work in the City.
At the end, many boys' parents said it was "healthy experience", though mentioned that this introduction (mainly communication from the college) wasn't handled properly and that girls "were imposed on them". My assumption that some negative comments here are from these boys' families who paid for "boys only" school. Such as these objectification comments... According to my daughter's insights, boys gossiping and "ranking" girls regardless of if they at Wincol or not as they not only attending regular socials with local girls' schools like SS and some of them have sisters and other friends/family connections there. They do this about pretty much all private school girls in Hampshire/South through social media. But needless to say that girls do the same.
As for sports, my daughter enjoyed playing Winkies and rowing, and was in Marines Cadets (even got a rank). And yes, girls didn't have lacrosse (not sure if some asked for it), but they had netball and fixtures with other schools.
Finally, my younger daughter wants to go to the college too and she is gentler, softer one. I feel that she will be fine at Wincol but most likely form friendship with different kind of girls/boys, eg music scholars, theatre circle, arts.