I have belatedly thought of another route to examining this oddity. Apart
from Siggi and Carsten contacting me directly, maybe others might like to
give it a try? My email address can be extracted from that which appears on
Tekscopes, but it is:



Colingherbert(at)blueyonder(dot)co(dot) uk



I will reply directly to any messages that get through to me, so as not to
take bandwidth from Tekscopes.

TIA, Colin.