Like I've said as well, it depends on your journey time too - shorter journeys will do nothing for your fuel economy either.
My 1.2 dynamique only used to get 36mpg on the daily drive for exactly the same reason the 197 gets low mpg, my journeys are way too short to get any kind of economy - they're literally 10 minutes, if it's any longer it's sitting in traffic, which again does bot all for your mpg.
Maybe that's the case with Marty? Maybe he has a heavy foot? Maybe he's got a fubared 197 (welcome to ze club). Who knows, but we can all comment till we're blue in the face about the 197s economy, TBH.