Mrs B, try 'Unwins Annabelle F1' seed. Not cheap, but can easily be sown in seed trays, plonked in a warm spot, safe from slugs etc.
This year is the first year I've managed to get a crop worth using, and there are plenty more to come along!
The seeds are big enough to sow singly, an inch apart both ways, and I do a tray every three weeks or so!
Worth a pop?