Yep it does feel a bit like joining the Masons, all a bit too much 'you scratch my back...', I'm squirming just thinking about it. Another point with Business Link, though not networking related, is their Select Supply scheme. I've (after a 2 month process) just got on to it. It's basically a list of approved suppliers so if anyone contacts your local Business Link for branding/ marketing advice etc then they may pass your details over.
The process is a bit of a nightmare, took about 2 hours to fill out the application, had to send a copy of my degree certificate and PI insurance as well as getting replies from 3 clients to recommend me. Only just on the scheme so will keep you posted as to whether it is worth the effort.