I there any site which tells you this, for United Kindgom, Im basically doing a report on this, and cant find any sites with this information.
You can't find, 'cuz there isn't any point in making such a website. So the old people using mobile phones are becomming more and more. Of course they aren't many. I can't give you statistics, which I'm sorry for, but you should try to connect with some media, that can do that for themselves and for you.
I think in this world of the communication 35% to 55% people uses mobile whose age is bigger than 60.