By this time mid September, you can sense the garden slowing down. The days are shortening, and with it temperatures are falling and we have lower light levels. Whilst it all depends on where you garden, it is noticeable that tomatoes are ripening more slowly. Unless you want to make batches of green chutney, it will be necessary at some point to cut your losses , and the tomato vines, to bring them inside to ripen.  

When it turns cooler and the tomatoes seem not to be doing much, cut the vines so that you have batches of tomatoes still on the vine. Bring them into a warm conservatory or porch  and its good to lay them out on newspaper. If space is restricted you can put them in a dish on a warm sunny window sill. The extra warmth inside and sun will ripen most, but probably not all. I find when the tomatoes first come in and there is still quite good light levels and sun, the tomatoes continue ripening well,  but sometime later in October/early November, they can look less appetising and then it's compost time for any which are left. The good news is that bringing the tomatoes in from outside or the greenhouse, into a warm place inside, will definitely ripen  the majority. I have used this method successfully for many years and never yet made chutney.