For those living in (or visiting during the Summer months) the south-west of England...
...Abbey House boasts a spectacular (according to their website) 5 acre English garden, which is open to the public, and is home to local 'celebrities' Ian & Barbara Pollard (AKA "The Naked Gardeners"). Every Year, during the months of late May until early September, the couple host 'Clothing optional' days, which again, are open to the public. I dare say that there will be CFNM experiences abound, but I cannot speak to the male to female ratio, nor to the demographics of any females that may attend.
Below is a link to their page, with days and times for their 2015' events, which is usually updated in the 1st week of April. (Note: I have made the link unclickable, as to not flood their site with traffic that will be linked back to the Village - Simply copy and paste, then swap the 2 X's in hxxp, for 2TT's, and you will be good to go)
hxxp://www.abbeyhousegardens.co.uk (click 'Events' then 'Clothing Optional')
Now, obviously this is a non-sexual event, designed for those that enjoy themselves a pleasant mixture of horticulture and outdoor naturism - So if you are looking for something a little more 'full on', then maybe this one is not for you.
This has been on my to-do list for a few years now, and just as before, I am hoping this will be my year.
Travess