Might be better to put them on a windowsill (inside) where it gets sun (if there's any) and put a ripe tomato with them - a sunny windowsill often works.

How long ago did you plant them ? I don't understand it , mine have been ready since the end of July. are you feeding and watering them well ? Sorry but can't help any more .

No idea where you are but we are having a great crop of tomatoes... to the point we are giving away.

Thanks for trying.I know the reasons they are late,I am looking for a solution.
I'm in Manchester.

banana and paper bag or sunny window sill don't know of anything else you can do sorry Jim, unless you like green tomato chutney.