I have now realised I completely confused my own issue by misreading all the responses until now. It may have been something to do with that little glass of wine that may have passed my lips last night
Reason I asked the question is that it was DS's birthday yesterday and DP was waiting for the song to be sung before the blowing and I was waiting for the blowing to sing the song. Lead to quite an uncomfortable silence, I can tell you!
Obviously it is just my side of the family that is odd. (Where's the festive biscuit face??) Looks like I might have to change the habit of a lifetime!!
Thanks everyone