What are your reasons for not wanting it? If it is because of the autism thing rest assured there is no link between the MMR and autism. There was only one fulty study that brought on all the hype but there has been tonnes and tonnes of research demonstrating no link at all.
Byron will get the MMR. I had wanted to get the injections done separately because it's my feeling they, in general, get given too many together and too young overloading the immune system. I've heard it's around £70 an injection though so we can't stretch to that.