Hi Davey,
I hope this helps more than it adds to any confusion regarding your MPG question.
I’ve owned my 1996 Defender 300 TDI for 53 months and have logged all fuel consumed – I started this because, like you, I was unsure what MPG to expect. I’ve kept the monitoring up out of interest, as it’s easy to do and also because I thought it would be a useful indicator of any ‘MPG faults’ that might arise overtime.
The Defender is a second vehicle, used mostly in winter and at other times to transport the dogs to the park. My journeys can be summarised as a mix of short 10-15 mile park trips and longer Winter trips twice a week of about 90 miles between Sep and January – these trips include about 10 miles of ‘off road’ activity.
My average over 20485 miles is 30.89 MPG. A lot less than my car but then that doesn’t bring a smile every time I drive it! Buy one!
I would just add one complication regarding achievable MPG which hasn’t been mentioned by anyone so far and that is you will have noticed the large range of tyres and sizes available for Defenders – mine are 225/75 x 16 M T’s. I’ll leave it to those more knowledgeable than me on this Forum to comment on what effect tyre size has on actual recorded miles travelled.