Rescue me

I'm fairly green fingered and my Mam always said I was a natural at taking care of plants. However, I've never, ever been able to grow a sunflower. Never could as a child. Never could as an adult. Each year when the kids have brought them back after planting in school or preschool I've managed to snap them, under or over water them or have them eaten by slugs or rabbits before they reached more than a few inches. This year, however, I've managed to grow some whopper sunflowers from seed. Some of them are about as tall as me. I've been very protective of them, as you can imagine. They are my brood.
So you can imagine how I felt when I found this scene in my garden this afternoon. It's very windy again today, and a gust must have caught the biggest one and snapped it clean off. I hadn't tied it to its stake (I've done that with the other big one now). I've tried to rescue the snapped one by repotting into damp compost and moving it to a sheltered position next to the house. It's so close to flowering! I hope I've done enough. Any other advice would be most welcome!
244/365 completed!