Hi Mark, we're not ignoring you, honest!
I've only gone on a couple of the London Sky Rides, which I think were classed as City Rides - mass events on closed roads. Looking at their simple Sky Rides, though, they look like they should be fun and, unless you can find a ''Ride Strong +'' route, they look relatively easy - rarely more than 2 hours riding time with comfortable average speeds.
Why not give one a go and report back? There's nothing to lose.