I had a Vauxhall Ampera on a 3 day test a couple of years ago. Pretty much same tech as the GTE, 30 odd miles on electric and then the petrol for when the electric runs out.
I did intend to use the car as I would normally over three days, which as a Service engineer can vary pretty much, but in reality I actually gave the car a pretty good thrashing at times to see what it could do and to show interested friends who came along for a drive round the block.
Anyway. The car arrived fully charged on the battery and I reset the mileage and MPG counters. I topped off the battery each of the 3 nights from my home 13pin plug and a couple of times partial charges when I had popped home between trips. The headline figures over three days was
177mpg over a distance of 183 miles. Remember this included a few foot down acceleration test to see what it was like as well. Have to say the performance and pickup was pretty impressive, although the price VX were asking left some of the interior materials looking poor.
I think what got the figure so high was that I learnt pretty quickly where the electric made the gains. On motorways and A- Roads I kept it in the hybrid mode, so the petrol was working with the electric (think that's how it works). What I did do though and I think is key here, was to pop it into electric when in traffic, or roundabouts, pretty much any sort of stop / start driving.
Anyone chasing MPG on a run in their car will have noticed that 55mpg figure soon takes a downturn when you leave the motorway or get into the town. Pop this into electric mode and save the fuel in those circumstances.
After a while changing the driving mode became pretty much natural. My only criticism is that these manufacturers should put the driving mode switch on the steering wheel, where it is easy to toggle and less distracting than a centre console switch or info touch screen. I guess a really clever next gen system could use a ECO/GPS mode where the car could choose the best electric/petrol/hybrid mode for the given geography and road types.
I will definitely consider one for my next car if the maths work out on a PCP etc. Just remember to keep a 300 foot electric extension reel in the back of the car for those opportune topup moments
Did anyone notice it doesn't have Xenon lights on the VW specs page?