The Membership module itself installed and works flawlessly.
I should say that I'm not exactly using this module as intended. In fact, this is a heads-up to all you shopping cart people (Virtuemart etc) who want to offer recurring billing for an Auto-ship product. I've searched for a year for this feature and the OSE module provides exactly what I need albeit outside of virtuemart.
I needed some support to get it to work the way that I wanted it, and their guys are really on the ball. Even though they are based in the UK, and are 6 hours ahead of us, I received responses to support inquiries at what would have been 8.30pm UK local time, on a Friday night!
Anyway, to reiterate that I'm not using this exactly as intended, but it's been a first rate experience start to finish.