Lee Valley VeloPark - taster sessions!

I'm trying to book my "improver" session on the line, but can't find out how to get the option to show.

The option shows on this page
http://www.visitleevalley.org.uk/en/content/cms/london2012/velo-park/track/track-accreditation/

But, when I login, it only offers Taster sessions, vouchers and sessions for already accredited riders...

Do I need to wait for them to update my member details after the first session still?

In theory yes, but it is obvious that this process isn't as slick as it should be. You could try calling but I think there are only 2 on the phones so don't be surprised if you don't get through.