OK, so having looked at this a little more, it really is tough to discern the boundary between amateur and pro. The major issue is juniors who are in the BC Development program and so are not full-time, but who quite often graduate to the Academy where they will be. Going deep with amateur rankings, therefore, requires quite a bit more research but to keep with the spirit of identifying the best true amateurs, here are the Cyclostats British Amateur Bests.
Kilo: Bruce Croall, 1:03.212, 2013
200m: Jon Paul (junior) 10.175, 2011
Best non-junior: Jonathan Mitchell, 10.262, 2015
4k pursuit: Graeme Obree, 4:20.894, 1993
500m TT: Danielle Khan (junior), 35.345, 2013
Best non-junior: Julie Forrester, 35.448, 2002
200m: Rebecca James (junior), 11.093, 2009
Best non-junior: Denise Hampson, 11.508, 2003
3k pursuit: Emma Davies, 3:35.069, 2004
We will keep track of these as we go forward.