Has anybody used Millers with the 1 litre petrol engine and had power train faults show up?  I’ve had this twice, and had to have the PCM  reset at the dealers each time.

what ratio of additive did you put in ?  using the correct minute dilution rate, I'd be surprised if the car could detect let alone react badly.... 

however the world of nasty badly written defective junk software has been alive and well for at least 15 years.  gone are the days of sad old duffers, writing clever small code that works. today the three year olds compile bloatware, using thousand of megabytes of utter junk, with zero understanding of how or why.  The fact the anything actually functions at all, is pure luck these days. 

for the first 60k miles of any vehicle, just buy petrol from a proper supplier like BP, Shell or Esso.  Then there is no need to put any other expensive stuff in the tank