I think the limitation is hall space as i think that is reached before the 13 heat of 10 cars limit is reached, and last year was rather full at Batley and York has less space to pit in (unless the work carried out changes that?). So I would recommend not presuming a late entry is okay, to avoid dissapointment, entry will be through your regional representative and NOT direct to the club or BRCA.
Your regional rep is likely to hand out the forms sometime in the new year, and it is beleived to be by qualification through the regional winter series - but whether it is or not
, I think the BRCA do attempt to accomodate within reason.