I presume that East Frith is on the level section and not the adjacent steep gradient?  While Grange Knowle is not on a steep gradient I do wonder if it is sufficiently steep to have attracted adverse comment from the Inspecting Officer especially as there is a steep gradient for over two miles on the Sayersbridge side of the station - is that section double line or single?

I've tried to make sure the stations are all either on level track, or no more than 1 in 300. My yardstick for that maximum is that I believe Parkstone station in Dorset is on 1 in 300, with 1 in 60 before and after it. In the fiction, the line is single (always has been, though might one day be doubled).