Hi Darren,
You could try harvesting some now and watering a few to harvest later, I am finding it hard to judge vecause they are later than usual and are enjoying heat more than the usual rain. If any tops fall over that suggests harvest time has arrived. I have planted some winter cabbage and kale between my Solent Wight, which is still growing, but all the others are out and drying beautifully.
Incidentally, bindweed loves this heat 