my 2,500 km review on the bike
https://youtu.be/aJQW79aolA4
Great stuff. It's hard to find a reliable long-term review of a stock Interceptor. Mine has 3,500km up, and the experience has been more or less the same as you describe. I've also had some false neutrals between 5th and 6th (on the way up only), but they are getting rarer, and preloading the shifter, or just taking your time, sorts it out.
And I too put in an interim oil & filter change -- at 3,200km (although my Interceptor is in mph on the clock) -- using Motul 7100 4t 10w-50. Red, with Ester, like Silkolene but a hell of a lot more reasonably priced. The drain plug came out clean with absolutely no debris on it.
I'll actually re-watch this vid to make sure I've got all your observations. So far, I'm really happy with the bike in every department. I'm still mulling the booster plug, and happy to take my time on that one, as I have other little improvements in line before it.
(So far, no train has come over a bridge to run me over. )