When did this become part of the county of Cheshire? - a simple question to ask - I once worked this out but I’ve forgotten the exact answer!
Stockport always referred to itself as being in Cheshire but after taking over the Heatons area, part of it was within Lancashire.
Yes this part does confuse me (not coming from the area myself), when on Ancestry you see some people who have put people in family trees birth places down as "Heaton Norris, Lancashire," and others have it as "Heaton Norris, Cheshire." Thank you.

Post 1835, it should be Heaton Norris, Stockport; although there are still people in some parts of Stockport that think they still live in Cheshire
I remember once describing a house in Heaton Moor as “
being of little archirectural merit” to which the owner responded that his house had “
once been featured in Cheshire Life”. I refrained from telling him that it had never actually been in Cheshire!