Thanks for your reply Tim. I have about 250 tomato plants plus aubs, chillies, peppers, cues and Cape gooseberry seedlings. I also have pots with seeds of squash, runner beans, French beans, peas and bedding plants which have been planted this weekend.
The timer allows me to set the watering times up to 4 times in 24 hours. I think I may have to buy some capillary matting from what you suggest. If I dispense with the sprinklers, would a seep hose give sufficient water and would I have to have it running all the time to ensure it gives adequate water? I may have to divide the main hose and have two seep hoses coming off it as some of the plants are on the ground whereas others are on staging.