Kay, Carin, Ruth - thanks for all of these comments. There is a lot
of common points you make and, like I said to Kelley, a good clean
out and empty runs with different water and mild detergent is my
first plan of action. Did a quick check for ammonia Ruth and looks
like I can get it from Boots here in UK no problem. I'll go with the
coke as I have it at the moment (and I don't even want to think of
its similarities to ammonia!) Thanks folks - invaluable advice. All
your tips almost make it worth having a disaster at the outset!