Time rolled around for my second inter-service oil change so I decided today was the day. Remembered the drain plug is a 17mm bolt (thank you John Grinsel) and where to access it. All told the entire job was probably 15 minutes? A vast improvement on the first time I did this bit of a job. The manual is a bit vague on the capacity for the 10-40W oil to fill up stating:
Full capacity: 1.1 L (1.16 US qt)
Exchange capacity: 0.9L(0.95 US qt)
After leaving it to drain fully for about 10 minutes, I put the sump plug back in and decided to go right down the middle with a measured 1 litre of oil poured in. Guess what, spot on the top of the full mark on the dipstick. Will no doubt need checking and possibly topping up in 100 miles or so, but one litre seems a pretty good start point?