Welcome Simon, and sorry for the late response. You've probably done your oil change by now, but just in case.......
Warm engine, undo drain bolt on oil tank, and use some sort of make shift funnel set up to keep the oil from running all down the bike! Also, there is a drain bolt on the left side, low down on the crank case. The filter is behind the small cover on the right, held by three bolts. When replacing, make sure the spring is seated in place first, before nipping it all up.
To check for correct oil level, take bike for a short run, to fully warm up engine, then let sit at tickover for one minute. Switch off, then remove dipstick from oil tank.
