There are not that many Sponsored Reservists and they do not do AAR.
AT routes are completed by RAF pilots but occasionally are suplimented by Air Tanker Sponsored Reservists. Some training is also completed by Air Tanker Sponsored Reservist instructors.
You are correct, a couple of the SRs with no previous military flying experience and have been awarded RAF pilot wings. SRs wear RAF uniform when engaged on military duties and civilian uniform when not on SR duties and working for Air Tanker.