[Past master]

Given that the problem is diesel dilution of the oil, I wonder why the need to change the filter? Surely all you need to do is let out the old oil (and diesel) and pour in the new? Then change the filter as usual at main service. Am I missing something?

 

[Past master]

My fuel consumption seemed to improve after an oil change too. Back to normal now though.

 

[Past master]

Not necessarily. Mine recently went from 3800 to 4000. The figure is produced by an algorithm based on the number of failed regenerations to date. If your driving habits change - ie you do a few longer journeys, the calculation will take this into account and alter its prediction.
It's not a bad idea to get the oil tested - plenty of comments on this forum about that!

 

[Past master]

My (first and only so far) service included brake fluid change in the price. I checked beforehand. No guarantee that they did it of course, but I've no reason to doubt them. That's Marshalls of Peterborough. Cost was £520. If I were up in the north I'd get a quote from TVLR in Gateshead - they were always good value in the past, but I've not used them recently.