From that you can deduce that the decision to move you up is made by the session coaches and that you need to inform them that you'd like to be considered for progression before the start of a session.
I think it's up to the individual to decide if they think they are ready, i.e. if you find the pace of a novice session too slow then you should ask to be moved up.
The information on sessions is here;
http://www.hernehillvelodrome.com/information/track-sessions
From that you can deduce that the decision to move you up is made by the session coaches and that you need to inform them that you'd like to be considered for progression before the start of a session.
I think it's up to the individual to decide if they think they are ready, i.e. if you find the pace of a novice session too slow then you should ask to be moved up.