Well we are way off topic, but...
Actually I am in Australia, and there has been a huge push over here to educate everyone that it is Down Syndrome, and not Down's Syndrome, hence my correction. Usually Australia follows the UK's lead in language. I'm sure there is lots of reference material on the debate about the renaming, and why it was done. Generally though, in naming things, we drop the possessive "s". For example, the colloquial "Murphy's Farm" becomes the official "Murphy Farm".
I see though that you are correct. The UK still uses the name Down's Syndrome.
http://www.downs-syndrome.org.uk/ Although they quote articles that use "Down Syndrome".
But Australia and the international body, or at least one of them, use Down Syndrome.
http://www.downsyndrome.org.au/ http://www.globaldownsyndrome.org/Actually the World Health Organisation accepted the name Down Syndrome in 1965, dropping the previous common name of Mongoloids. It seems it took some time to catch on though, as even the reference quoted by the WHO uses the term "Down's disease", and was written in 1979. This quote from the global site.
http://www.globaldownsyndrome.org/about-down-syndrome/history-of-down-syndrome/research-and-medical-care-timeline/1965: WHO accepts the name Down syndrome as standard
A delegation from the country of Mongolia sends the World Health Organization an informal request to stop using the objectionable terms of “Mongol” and “Mongoloids” to describe people with Trisomy 21.
The World Health Organization accepts the name Down syndrome as the standard accepted terminology. The term “mongolism” is removed from most, but not all, references. Mongolism references in scientific literature persist into the 1970s.
Howard-Jones, N. On the diagnostic term ‘‘Down’s disease’’. Med. Hist. 23, 102–104 (1979).
Ain't language wonderful?