Just change the 'stat. The job will use very little coolant and not many tools. Job done and the engine wont be running cool and wearing faster as a result.

Those mpg figures are good.. our 1.1s are very similar to those 1.2 figures quoted.

Agreed..any stat that cannot maintain mid point on the gauge wants changing.. the primitive stat on the SAFE motors is cheap and simple to swap.. the 500 style with plastic unions.. a bit more fiddly.