This is a tricky question. Having seen so many ovens and spoken to lots of customers I think it can come down to this. If your oven is not too dirty you can probably wait until after Christmas, if it is really dirty, smelling and smoking get it done before.
I understand the impulse of the pre-Christmas oven clean. You have family in your home, and you want everything to be perfect for the big day. However I would say that if it is not too bad you are probably best to wait until the new year. Your oven is going to be used heavily over the Christmas period and just think how nice it will be to have a sparkly oven in the new year.
If your oven is smoking or smelling you probably should choose to get it cleaned straightaway because no one wants that while they are crooning along to Cliff Richard singing Mistletoe and Wine on Christmas day morning.
Whenever you choose to have your oven cleaned we are here to provide a fantastic service the whole year around.