I would not be happy with that amount of oil being used. Are you adding the correct engine oil. Have you looked for possible oil leaks after parking and as said..DPF problems down the road.
As far as I’m concerned, if the oil meets or betters the MB recommendation for the engine oil, I will buy the cheapest. This along with the correct oil service is and how I’ve always run my cars.
I was asked if I wanted the MB service plan when I ordered the car. I didn’t but had a nice chat with the sales executive who was very knowledgable. One thing he said was to always fill the engine with the correct spec oil. This goes for all the main engine fluids, oil, coolant and gearbox.
I would say, if you have not got a Pela, consider buying the unit for Lidi. Saves moving the dirty form the Pela to container and looks a good bit of kit....if it works for a few years!
I’ve never flushed. If your car had the correct oil and filter service and you know it has, why would you. The last thing you want is a bit of leftover flushing oil in your sump.
Just change the oil and renewed the filter this afternoon as the last of this good weather made it the perfect day for me. I have the Pela, same as W1ghty and been using it over the years on our cars.
One thing to ensure is that you have the correct engine oil spec for the car. If it says Low Ash C3 oil then thats what must be used. You can damage and shorten the life of the cars cat by adding the wrong oil. A good run using a motorway a few times a year will bring the engine and exhaust...
I’ve used Tayna for a replacement AGM battery. CCA was better then the original but not a lot. I had a chat with them just to be on the safe side as I had no real understanding of the AMG battery. The best deal with them was for a Varta and 4yr. Very happy with the service and price.
As for your gearbox service, had my 7g+ oil and filter changed a few weeks back by PCS who are an indi and are on the recommendation list on this site. £200 inc.