Dave Hill wrote:
Tomatoes are perenials, commercialy they are often croped for 11
months.

But not in the UK, surely?

The old advice foe the home gardener is to cut off the stems above the
top truss of green tomatoes i Sept. to direct the energy to the last
fruit , but if you make green tomato chutney the why bother.
If you heated the greenhouse you are growing them in then you could
carry on croping them.

I didn't think it was the heat so much as the sunshine that turned them
red, so once you got to the shorter days, they would stop ripening.