There will be another intro ride session. Probably the second/third weekend in February. Look out for the event which will be posted.
Wednesday evening Velopark sessions are not official.... I think ICC members turn up on a ad-hoc basis and just pay to ride. There is a forum thread for that session if you need more info.
Yes, there are Saturday club rides. Training rides in Regents Park, and a club ride which heads out on the same route every week into Essex. Both have different meeting points - look for the relevant threads on the forum.
@Laura
+Ceci
Ta!