Uneven ripening and fruit that tastes ‘flabby’ (low acidity) is usually due insufficient potassium. Feed every watering with a high potash tomato feed. Have your soil analysed and apply high potash fertilizer before the next crop (if required).
Early in the season, there can be large differences in temperature between the warm, sunny days and cold nights. These wide diurnal fluctuations can cause the leaves to roll up or curl. This is due to large amounts of carbohydrates accumulating in the leaves because the nights are too cold for the plants to assimilate them. It is usually a temporary problem that cures itself as the nights get warmer.