West London is the hottest place in the UK, but also the driest, so the young vines have needed water to keep them going, until 20 mm of rain fell in 3 days, thankfully. However, this raises the spectre of the mildew which ruined the entire crop last year, so I resprayed with Systhane immediately after the first downpour.
I tested the soil and found it too acidic, with a pH of less than 6.0, so I applied lots of garden lime, which is basically calcium, which 'unlocks' nutrients in the soil, and magnesium, which boosts disease resistance. The recent rain has washed this down to the roots with stunning results. The grapes have swelled to almost double their size and isolated pockets of mildew have been stopped in their tracks.
The scale insects have been exterminated and a small colony of aphids has been destroyed. I am in the process of laying down slate scree on top of the bark chips and rapidly decaying cheap weed control fabric. It's expensive stuff, so the garden centre is selling it half price because nobody buys it. I am now their best customer for it, but stock is running low. Apart from being a permanent weed/moisture control system, it adds a heat storage radiator effect and provides a hostile environment for pest eggs and fungal spores.