Posted: 23/08/2013 at 16:31
We live in Hampshire and have the similar problem of fruits very slow in ripening. In the Spring I sliced two growbags in half across their width and stood them on end, sowing one tomato plant in each bag after mixing growmore with the soil. The four plants are inside mini greenhouses with plastic covers, open at the front, and have produced an abundant amount of fruit. They are finally showing signs of turning light green/yellow and should ripen in the next couple of weeks or so.
I use this method each year and it is very successful, the bags are connected to my automatic watering system which waters them at 7am and 7pm for two minutes each time.