Brandon is back and my grinder has been looked over.
They advised on a small issue where the brass washer was upside down which they corrected, and they also noticed a dent in the bottom wood insert which was a result of my over enthusiastically removing the funnel which came off suddenly and bashed the bottom resulting in said dent. However they have replaced that for me for free which was nice of them.
They ran some tests and did see the same large jump in shot times from 0.1 to 0.0 of 15 seconds which I was seeing, and different from @mackerel and @Tjyven . However by relatively small (I think) changes in the RPM they got 3 second differences in time.
Test 5 vs Test 7, ie 700rpm and a half notch change in grind size shows only a 3 second difference in time, which doesnt seem to correspond to Test 2 vs Test 3 at only 100rpm more. I am surprised at that, and will definitely be testing when it comes back.
For now I assume that 100rpm changes to week the time won’t make significant taste changes and is a different way to adjust the shot times. Thankfully Bean Conqueror measures both so should be able to record and understand how to adjust. And if I want to do more significant playing with rpm, ie 200 vs 1000 for taste from different fines % I can still do so.
Its still a magnificently built machine, albeit with some quirks, and the customer service is superb, so hoping this gets me a useable machine for not just espresso generally, but also the types of bean, ie medium to light, and shots, ie long preinfusion pressure profiled with fine grind, that I like.