Down To The Last 3

[Shazza60]

49. Take away the intermediate class (6)
89. cloth heavyweight is suitable for school
91, A helpful supportive person after the German returned from such a university (8)

[JJ109]

49. look up Billy Bunter
89 Derbyshire School
The German reversed plus a building material

[Shazza60]

Got 89 and 91
Just 49. have a few ideas... Campion or Magnet

[goodgoalie]

Remove

[JJ109]

Goodgoalie has provided the answer
https://en.wikipedia.org/wiki/Billy_Bunter
"...He is in the Lower Fourth form of Greyfriars School, known as the Remove, whose members are 14–15 years of age. Originally a minor character, his role was expanded over the years with his antics....

[JJ109]

Thanks for best answer

[Neveracrossword]

Aah, the Rainbow Quiz - I wondered why these were familiar!