Even though it appears to be configured for the UK keyboard, it's possible that something internally has got confused. I had a similar issue with my EeePC last week, so I told it to use a US keyboard, which obviously didn't work, and then told it to use a UK keyboard, which in effect forced it to reload the correct bits, and it worked correctly after that. Depending on the system, you may find a reboot between changes may also be needed to promulgate the changes throughout (although this is more likely to be necessary on Windoze than Linux!)