Hugh Newbury wrote:
The unit was new in July 2007 and has behaved up to now. If the sensor
has failed, can I fit a new one myself?

They're easy to fit, if it turns out you need a new one.
--
Steve Loft
Sanday, Orkney. 5m ASL. http://sanday.org.uk/weather
Free weather station softwa http://sandaysoft.com/
uk.sci.weather FAQs/glossary/etc: http://weatherfaqs.org.uk/