mmm, just trying to remember what i did when i got mine recently.....
I filled the form in and sent it back to cough to the speeding. Then after a while they sent me the result - i.e 3 points and a fine. THEN i had to send my licence in for them to HANDWRITE on it in pen.
I would just send the form off before you go on hol and don't worry about it. At the end of the day once you've done that i'm sure you'll be fine - your licence etc could even have got delayed in the postal strike or lost in the post. Once you've admitted it i don't think you will be top of the pile.