Always check the dates on things. This first started circulating in Spring '07 and I can assure you from one of my best friends who is a head of history at a comprensive, all they ever teach is WWII and the holocaust. Practically every year is taught it as his school, so kids go over it year on year.
More information is here
http://www.snopes.com/politics/religion/holoca ust.asp
There is only evidence that 1 school ever actually did take it off the syllabus, and for what it's worth I think that it is totally incorrect to do so. However, please note that it was a single daft school and this is not something to over-react to.
Sadly, there will be multiple postings below this about how muslims are taking over the country, or saying "Even if this isn't true, what about all the other things they do....". And then a couple of months down the line people will have forgotten that this isn't true and start bringing it up in conversation about how the bl00dy muslims stopped our kids from being caught. And thus the pointless cycle of mis-trust continues