I also have a drink regularly, just never over the top, and have never seen or heard anything which would suggest that it could have any negative effect on HRT. Same with missing a pill from time to time, whether it be spiro, E or whatever...Sometimes you will actually forget because you are in a hurry or whatever but the effects of such an omission would, IMHO, be absolutely insignificant.
So relax and enjoy the upcoming events and if a drink or two helps make them more fun for you so be it. I'd be more concerned if you actually felt you needed to drink to get through them. That can quickly become a very slippery slope...
Hugs
Donna