A TA soldier acted terribly at a military function as a guest of someone else. Towards the end he was loud and swearing in the smoking area and offended some female guests (wives of serving soldiers). He wasn't actively being aggressive to anyone, but obnoxious, hitting on the women and generally being a nuisance and an embarrassment. He was not there in a military capacity, however what options are open? Would a letter of apology from him suffice or should I get in touch with his unit?