I think it's up to 1.10m. I am also planning to take it next year, will probably call the BHS at some point as the syllabus doesn't give any heights/dimensions.
I took mine at Huntley and the jumps are meant to be 3ft 3- 3ft 6 both show jumping and xc, the showjumps were well up to height but only one xc fence was.The horses were great there!