Answered separately

I would never water a lawn. It will recover after a dry period. Established shrubs are better off not watered either. Once they've been in the ground a year or so, their roots should be going down deep and should be able to survive a UK style drought. If you water them, you encourage the roots up to the top of the soil - not where they should be.
The only shrubs I would water are newly planted ones. They need a REALLY GOOD soaking about once a week, but only if there hasn't been any rain in that time. Just pouring on a little dribble of water every day does more harm than good, as it encourages those roots to stay at the surface. You need to give enough water to wet the soil at a deeper level where you want the roots to develop so that they can look after themselves in the long term.