A whole series of fair testing procedures I worked out for trouble-shooting my radio problem proved unnecessary, ultimately, because on the first test my IC-A22E (hand-held, with whip aerial and stand-alone battery) failed to receive a tansmission, though it sent clearly. I got an Rx on my screen but could hear nothing. So I have packed it up ready to send back to Icom for repair.
I tested my aircraft aerial with Craig's radio and it worked fine, as did my microavionics headset. Once I have the radio back I will use it with the aircraft power (already wired in) and the Flycom helmets and intercom.