No not miles off.... just about spot on! Well done. I agree it looks like one of those Amanita ochrophylla group species. A little atypical. Thank you for including images that show the different characteristics of the fungus from above and below, very important. Most probably A. ochrophylla because of the pale gills rather than deep cream coloured of A. ochrophylloides or A. ochraceobulbosa that has warts on the cap surface rather than the flat scales.