We are London based. We planted the seeds back in March and kept the seedlings in a greenhouse, transplanted them out about 3 weeks ago. The same happened last year with most of the courgette plants and none of the squashes finished the fruiting process, we managed to harvest a few courgettes though but lost most of them. The same seems to be happening this year, they start growing nicely and they reach a point where they become brownish and fall off.