No, there is not something I haven't told you.
As R is not working and I am, Jack has bonded well with R and they go for long walks. While Jack is content to sit and watch, he loves a rough game too.
Jack had a previous owner who could not longer keep him as she was suffering from a severe long term illness, so our friend took over Jack. We were there at the tearful handover some years ago and once the old owner left, our friend said that she did not like his name. R said, call him Jack, and Jack he became.
Before anyone asks his breed, I only know the Latinish/Euro name, Canine Alba de Fluffy.