I've got green tomatoes everywhere: greenhouse (in halved growbags), garden (growbags & ground), and allotment... but not a single one, anywhere, has even the slightest red tinge!
All the plants have been 'stopped', the side-shoots nipped out, the growbags are getting 'fed' twice a week... is it simply likely that the cool & wet weather has put the dampers on the lot?
I've never tasted green tomato chutney. If a colour change doesn't happen soon, I'm going to be drowning in the stuff.