Cinereous Tit in the UK?

Hi,

I've just recently seen a bird exactly like a Great Tit, but with a distinctly silvery grey back. It briefly flew to the kibble feeder, then returned to the nearby tree and disappeared. I'm fairly sure I've had a few brief glimpses before, but can't be sure.

Is there any possibility that it is a Cinereous Tit, or do I need better eyes?

This is just south of Leicester.

Thanks