Any one had any experience with Desire as we are planning to go there in August
Yes
It is wonderful, really wonderful and expensive enough to (almost) guarantee a high standard of clientelle. Top quality place and top quality Clients - more than you can say about the vast majority of seedy Swingers places in the UK.
Look on their calender and try to book when a big group is going and that will ensure an action packed week.
Only thing I would say to you is that Cancun is not an ideal place to go in August especially when you have so much choice anyway in Europe. Cancun in August is hot and humid and really far from comfortable. Try October to April if you can, the climate is somewhat more bearable.