Hi Mike - the machine I have is a H-axis Hotpoint WMTL79. I have used longer cycle times on occasion when I first started using Ariel Gel but after experimentation found that it made no difference. I use cold or 30 for all clothing. Once every two weeks I do a white wash (kitchen linen, towels etc) and I use 50 or 60 degrees for that. For white clothing like t shirts and stuff like that then I either use 30 or cold and have had 'brrrrilliaant' results. A lot of my white t shirts and tops have 30 degree or cold care labels and almost all of my Aussie Bum undies suggest 30 degrees or cold also.
I hear what people say about killing germs but as a previous poster from Oz has said, cold water washing has been around for years and many people use it and suffer no adverse affects. Incidentally, I have recently started volunteering at a local hospice for the terminally ill and had to attend a training course on infection management. We were told that as we will be wearing our own clothing, albeit with aprons etc, we didn't need to launder our clothes any differently and a wash in 30 degrees was more than sufficient. They also said it was not the length of washtime that made germ killing more effective. I am sure there are many here who will contradict this but I have used low temps for years, my clothes are clean, they do not smell mouldy or dirty, my washing machine is not smelly and I have never done a maintainance wash EVER in any machine I have owned and of all the people I have talked to about it, and it isn't that many, they have never heard of maintainence washes!!