Maybe a little harsh MrsP!
Although things do pop up from time to time, a big part of LL is to deal with these in the appropriate way as and when they do pop up, breaking the diet every time something pops up isn't really the right way to go about it. During the 3 months minimum we all do LL it is highly likely that something will pop up, be it a birthday, hen night or other celebration.
It is a test, one that can be hard to decide how to deal with.
I do believe that staying with your packs is the right way to go, and it is totally possible.
When I started LL I had 6 weeks til Christmas and decided that I would break the diet and eat, but by the time it came I had set my mind right and decided to abstain and I did.
Part of this programme (because it is so much more than just a diet) is to learn to deal with your life without food and you can't do that if you constantly break the diet because you have another occasion to go to.
I think you need to think long and hard about it before you decide for sure what you are going to do. Why do you think you need to eat and drink alcohol rather than stick to the programme?
If you are set on eating and nothing will change your mind, then stick to green leafy veg and plain protein like fish, chicken and turkey. Watch anything with sauces, especially creamy, and watch your booze intake.
Plan exactly what you will do. Packs for breakfast, lunch and then salad and protein for dinner, try and limit the booze, alternate with something non alcoholic, you may find you get drunk quicker than usual. Definitely plan when you are getting back on the programme 100% and stick to it.
Put yourself a week after the event and seriously think about how you will feel if you eat/if you don't.
Above all have fun with your friends.