72 hour Visa Free in Guilin

Hi, our travel details are:
1. Flying from Copenhagen, Denmark to Hong Kong and staying 3 days
2. Flying Hong Kong to Guilin, staying 72 hours
3. Flying home to Sydney Australia but have to change flights (same carrier) and transit only in Hong Kong for approx 4 hours (not leaving aiport)
Are we eligible for the 72 hour free option for the visit to Guilin.

I have looked at many sources of visa information and cannot find a clear answer to this, any help would be appreciated, thanks