David,
Honest opinion? That looks more 18th C or 19th C Victorian folly than anything 17thC, so yeah, more Highgate than parish graveyard. It's also going to seriously dominate your burial ground.
If it's the sort of thing erected by a local knob to honour his late departed or enclose their own mortal remains then it would be more likely to be built on their estate. If they were minor knobs they would be buried in the crypt beneath the church.
Impressive bit of kit but just doesn't seem to fit with the theme IMO. Obviously, your toys your choice.