Tomato change of plan

Much to my disappointment, the three Green Zebra tomato plants are failing to thrive. I planted one of these outside at the end of October (probably a bit early, in fairness) and one at the end of November, and they haven't grown at all. A third one was planted on the deck and it's doing a little better, but the two in the garden are a bust. Can you even see the poor little scrap of green just above the marigold flower in this photo?

Given how much better most of the other tomato plants are doing, and how many I have still languishing in little seedling pots in the conservatory, I think the Green Zebras have got to go. It's disappointing, but I'd rather have something else than realise halfway through the summer that I'm not going to get any fruit. My garden has no space for plants that don't pay their way in some form or other, be it pretty flowers or something to put on the dinner plate. There's a Sungold and a Cherry Sweetie that'll do nicely in those spots, I think, so it's time to plant them out!