The answer is No, no, no, no, no, no and no. Your other workmates wifes, GF's will have her sussed in 15 minutes flat and will tell their other halves after the party - that's going to be eternally uncomfortable for you after the event with all the snide remarks etc., (mostly from jealousy!) When you meet someone at a later date, you may take her to the same event in the future to the same set of people that you took an escort to - that's you on tenterhooks for ever!
The only way it would work is if you were the kind of person that was openly brazen and extrovert - "yes, i booked an escort for the party and then I fucked her all night long afterwards, she was great" I don't think that's you Anth..
Have you got a company notice board at work where you could put an advert on to say that you are looking for someone just for the Christmas party? You never know your luck!