Hi Guys

I am retired and have a diesel Golf for economy (2003 35k miles). I do a regular 100 mile motorway run to Cambridge to see my daughter and grandchildren. I usually get over 55mpg each way. This has dropped to 44mpg for the last 3 trips. I booked it in to my local VW dealer for a check. They checked the electronic stuff(?) and the emissions, slackened off the handbrake, pumped up the tyres etc. They couldn't find anything wrong at all - hence no charge. Still running at 44mpg or thereabouts.

I would appreciate some sensible advice, the receptionist suggested I trade it in for a new one!

Any ideas?