On a 300 mile round trip from South Wales to Heathrow and back last weekend, the treg returned the following MPG: -
cruising at 65 nearly all the way, at the half way point it was reading 35.5 mpg.
After collcting wife, child and a suitcase....and probably battling a headwind, by the time I was back home the overall round trip average had dropped to 32.5 mpg.....Still not bad, me thinks.
My long term average over 10K is reading 29.7, but this has been after some trips towing a caravan as well.