Thanks for the link, but I do find it a little surprising: the question was asked, and answered to the effect that the rides can be done in any year (within the six year limit, obv) and any order - which doesn't strike me as much of a series ... The format of the claim form supports this, mind, as it asks for details of your 2 200s, your 2 300s and so on, rather than setting them out in series order.
I've suggested to Chris Crossland that as ACP Correspondent, it might be worth asking for formal clarification.