Sorry Chris but I've only just seen this as my computer has been playing up, but I would have liked to wish you a very happy birthday.
My eldest son's birthday is Christmas Eve, mine on 27th, my daughter's on 28th and a grandson's on 2nd Jan then a whole 8 days without any birthdays until a grandson's on 2nd January and another son's on 10th Jamuary. I'm glad to say that we do all remember (with a little judicious prodding from me) but I have always felt sorry for No. 1 son as Christmas Eve is the worst possible time, with everyone rushing around doing last minute errands.
It's too late for this year of course, but you might like to use my method next year. I never gave my husband the chance of forgetting birthdays or anniversaries. A short while beforehand I would say things like "It makes me feel quite old that I will be * next week." or "It seems incredible that we will have been married for * years on 24th May".