LGW lounge access

Hi,flying to LAS in upper on the 26/3 and know i can guest 1 person into the lounge,problem is the wife and 11yr old son are flying in p/e. I believe the lounge staff have the discretion to let another person ie son into the lounge.
Is there anything i can do before hand or should i just ask nicely at the lounge desk?
thanks in advance
Is there anything i can do before hand or should i just ask nicely at the lounge desk?
thanks in advance