I'm quite active in the WIB events in Glasgow and I should clarify that they are not "anti-men". They simply provide a positive and energetic platform for women who are thinking of starting up or in their first two years of starting up to meet like-minded people, potential clients, and potential suppliers.
I've been to stuffy networking events where it's the old boys club in three piece suits talking about their latest mega-bucks deal; for me, the sole trader in a creative business whose target market is fellow sole traders and small businesses, I'm wasting my time and money even showing up to those sorts of events. So WIB provides a great opportunity in that regard as well, and I've gotten my most energetic and best clients from there.
, to answer your original question, each regional WIB group is run locally, so contact the designated person in the local area you want to target.