Thanks for your help Jerryy, the lens was delivered today and I have found that attaching the lens to the X-S10 automatically selects the first lens setting in the Adaptor Settings (I had set this setting to 100mm with a suitable lens name). The EXIF data is updated accordingly. I will experiment with your suggestions but it seems strange that there is not a section of the manual that explains switching between lenses. I may email Fuji for the answer.
I must admit I am pleased with the lens and the way it works on the X-S10. I just need to get used to getting the point of focus exactly where I want it, a few more days of use should do it.
Thanks again, Dave.