I flew them for about 8 years on and off in the RAF. Did the trials on IRFIS.
Standard crew was 2 pilots, one nav. Others depended upon the task; so an AEO for all ILS calibrations and before IRFIS an extra AEO for the Theo talk down which was also required for the PAR. For freight and pax a LM.
The E3A had the big light because it was also used for PAR calibrations and without the big light, the Theo chap couldn't see you at long range.
I left before the Andover
PR finally arrived so can't comment on that.