British Motorcycle Charitable Trust
I've recently joined the BMCT. It was originally founded to build the National Motorcycle Museum, but is now a charity promoting heritage British motorbike engineering. As a member, you get free access to 11 transport museums (including Beaulieu and Sammy Miller's in the New Forest), all for £20 a year. Most of these museums make good destinations for ride-outs, and have decent cafes attached, so it's win-win!