I have it!
This morning I went back to the bedroom and sat on the bed next to Jeremy. We have faded black sheets- when I stood up there was a foof shaped wet patch just next to him. (I was wearing just a nightie with no underwear when I had sat down!) His face was a picture. Then he called Imogen in an said 'Mummy just wee'd on the bed!' I quickly tried to explain to her that it was not wee- but imagine trying to explain to a 4 year old what discharge is, and what it's purpose is! So I gave up!
Brilliant - bet when I pick her up from school today, her teachers give me a dirty glare!!!!
I can't wait until these unpleasant things stop happening!!!