The miles left indication on the GOM (Guess-O-Meter) is know to be poor (very poor) the way it works out the ‘Range’ is a complicated formula. when charged between 90-100% it uses the WLTP figures you see in the adverts for the car adjusted for the current temperature (more on that below). as soon as the charge drops below 90% it recalculates using a different formula, this time a blend between the WLTP figure and the previous driving style (and of course temperature adjusted) , this will often cause a sudden drop in indicated mileage range which can be alarming. then when you hit 50% it applies a different formula again, now its based on your previous and current driving style and temperature. often from this point on the range will not keep changing as much.
Now all that is fine but its still know to be pessimistic in indicated range. in fact most e208/e2008 drivers often ignore the range left figure and rather go by the state of charge indicator, SOME (not the slightly older ones) e208/2008’s will allow you to look how many miles per Kilowatt usage you are getting on average. this figure is better to check your range, you should be getting between 3 and 4 driving the way you are suggesting, more in warmer weather. so if you get 4M/KWhr then the battery in the e208 has a useable 45KWhrs so thats up to 180miles range, if you are getting 3M/Kwhr then just over 130 miles. BUT the temperature as a massive impact on range.
many users feel the range calculator on the Peugeot web site is about right so try that and see what figures it gives. (i tried to put a link here for that but it doesnt seem to let me 🙁 )
I am also the e208/e2008 forum and this is a very common question on there, some people are seeing less than 40 miles at just over 50% charge on the fuel gauge type display .
its really a bad range indicator on the display (bad as is design not a fault). when you put it back on charge what does the charger say as regards how many KW it has put back into the car? reset the trip meter after a charge, drive and record the mileage done on the charge, then fully charge it again and see the KWs that you had to put back in, dived that by the miles you have covered and see what the efficiency works out to, that may be of use if you have a real problem. let the garage know the results.
I have travailed a lot in a friends e2008 now just waiting for mine to arrive.
I Hope you get sorted
Have a good new year…. Paul