Not sure if
this link works but the GLA - LHR 'R' class booking rules state (among others):
THE FARE COMPONENT MUST NOT BE ON
ONE OR MORE OF THE FOLLOWING
BA FLIGHTS 2210 THROUGH 2217
AND
THE FARE COMPONENT MUST NOT BE ON
ONE OR MORE OF THE FOLLOWING
BA FLIGHTS 8700 THROUGH 8769.
GLA - LCY is operated as 8721/3/5/39 and 2213/15, so it seems to be correct.