Question Author
I use a hosepipe regularly, and watering cans, as I can then control the amount of water I need to use. I do have a sprinkler, but this can break fragile stems. I specialise in very rare Salvias from Mexico and South America, many of which adapt to the Surrey climate. (www.robinssalvias.com)...not advertising here, my site is only informative.
Thanks to all who have responded.....still no rain tonight!