Yes.
But my nana and dad put 'Anglican' even though they're not.
I can't think of why they'd do this at all. It's just going to skew the results and make the whole religious aspect of the census worthless, because so many Brits do this. I can't think why they would, so I can only assume they want to sabotage the results or something.
We are of like mind.
I would say people of an older generation here would tend to answer based on 'how they were raised'.
My Dad would put CoE, despite being mildly anti-religious, somewhere between deist and agnostic.