Not sure about the 10 plate autos but normally the Lexia was needed to read the temps of auto fluid before draining. I have drained the sump on a few 3litre and 3.5 litre French cars without using Lexia and just getting the fluid hot. So it would be interesting to see if Lexia really is needed on the latest ones. As usual the Auto's will be sealed for life.......or death. Every year is a good mantra for an auto box fluid change. You are dropping about 4litres each year. If you had no record of changes, and over 50k miles, I would drop the oil twice in as many months, to get more clean oil in there. Then resume, once a year.