You may want to join Twitter and do a more targeted search there. Through Twitter I found @hatfield_rosy who organises Athena business networking meetins for women (all industry types). This is her website on twitter http://www.phoenix-trading.eu/web/rosyholt/Store.php
I have run a number of marketing seminars for therapists in London which have proved to be a very good way to network and share ideas. I haven't got anything planned for Hertfordshire unfortunately but you can read the feedback here: http://www.energyanaturalfacelift.com/marketing-seminars-for-therapists/
It is worth starting your own networking group like Quantum Metta has done in London.
Also, the Wahanda team will be happy to help you I am sure!