Could be you started growing them a bit late, or that you didn't have them in full sun - they need warmth and sun to ripen off. If you started them late, then by the time the fruit's ready to ripen, it could be as late as mid September, by which time the sun has lost a lot of its strength and the days are much shorter.

Also if you live in the north of the country they will do much better in an unheated greenhouse. We can't grow tomatoes outdoors, just isn't hot enough.

You could try cherry tomatoes. They tend to ripen more quickly.

Also look for early kinds, such as 'Early Girl', 'Stupice', etc. They are bred to set and ripen fruit at lower temperatures than most varieties.

if they take too long to ripen bring them indoors in a dish they will ripen then

They don't get any sweeter, but they do get more tender, and less acid, as well as turning red.

thanks everyone for your responses fingers crossed this year