is there any chance they will extend another 14 days?

i have currently a 14 day visa - i am about to join my husbands z but waiting for the marriage certificate to arrive. i have already had an extension and feel we will not have time before it runs out. history....3 months, extended 1 month, flew to HK issued 14 days, extend 14 days. expires on the 27th. We are both british. my husband has his z already. What can we do?