Leeneia, Sungold are the only tomatoes I grow! Tomatoes only thrive in greenhouses in Cornwall as it gets a bit too chilly early and late in the season and is often too breezy in summer. I have an 18 foot greenhouse which, over the years, became gradually more shaded by tree growth. The three big culprit trees died of Dutch Elm disease last year so I had to get the tree surgeons in to remove them, and the resulting extra few hours of direct sun each day have had a miraculous effect this summer: I have a glut!   

I grow Sungold for several reasons: they are utterly delicious with a unique flavour; they crop right up to November; they are completely resistant to soil-borne tomato diseases, meaning that I can grow them in the same soil every year, you can never buy them ( probably because of their propensity for splitting a bit too easily, especially if you let them go a day too long dry at the roots.

I I always grow mine from seed, starting in April. We used to have a nursery that sold plants in individual pots cheaply (I need a dozen or more) but they are now astronomical in price bought that way. Not that the seed is cheap, but it's still much cheaper than buying plants.