The 1.2tdi can easily make 530km on hilly roads with silly speed limits so 800km when driven carefully and at a reasonable speed should be very doable.
I heard the low fuel ping on my last trip and managed another 130km before refuelling. This was on roads in Finnish Lapland which is very much flatter than I am used to and has a 100km/h limit.
I always have the air conditioning on and have not noticed much difference between Statoil (regular diesel), Shell, Esso or Neste/Finnish brands.
Here the Shell V Power is around 25p a litre more and I really do not think it would improve efficiency that much to justify the 2-3l extra diesel that would buy.
I think using busy garages would be a better bet than using V Power as a general rule as if the turnover is good their should be less opportunity for water/debris getting into the fuel.
I feel it’s my duty to contribute to this old thread – for completeness.
Basically, if you use supermarket fuel and only drive short distances the a horrible black glue-like sludge will start collecting in your EGR and associated pipes. Also, your turbo will also become faulty and eventually fail due to the variable power fin system becoming stuck/restricted/blocked.
I have been shown/have physically seen engine parts, removed from modern VW engines which have suffered this fate, by an audi master tech.
I support of the replies describing the ‘state of the art’ additives – YES. This is correct, it’s not really an octane ‘Boost’ OK, it’s (as has been described) keeping the engine clean and efficient – so it’s does not die of the dreaded ‘Black-Death’.
Not using my A2 TDI 90 very much at the moment #StayHome, et c. When I do (for work) it generally does get a decent motorway run. These days I run mainly supermarket diesel, with the occasional tank of Shell V-Power. I had filled the tank a few weeks ago with some supermarket fuel: I have no loyalty to any supermarket group, just whatever is a good price when I need it and am passing a filling station.
After using it yesterday the fuel tank was suffiently low for me to add 36 litres of V-Power. Based on no science, I decided the extra detergents in the premium diesel would be sensible in a car which sits there for days on end.
I heard on the news that Morrisons fuel had dropped to under £1/litre, so I did wince at £1.28. Preventative maintenance.