Fuel economy of XF 2.2 PL 61 plate

[jbb]

I would be interested hear from other drivers of the economical XF 2.2 with 8 speed auto introduced in 2011. Whilst I fully appreciate that you should never expect to achieve the over stated fuel economies in the sales blurb, but I am dissapointed to only achieve an average of 43 mpg with a high proportion of motorway driving at 70/75 mph and rare use of the sports function. This average has been routinely monitored using fuel usage against miles travelled and not using the in car computed mpg which is always overstating the mpg by 10% or more. (Monitored over 14,000 miles).