Many thanks, DRUK, for that most useful clarification !
HOWEVER ............, praise be ! I have gmail back ! ! !

Jhieminga's patience and hand-holding was successful ! The 'clincher' seems to have been the P/W change sequence, which, initially, kept advising "incorrect password" when the
first character of the P/W was entered

I then started the 'change P/W sequence' and followed prompts and, suddenly ... there was my account page ! ! !

In all honesty, I can't recall all the individual intermediate steps - 'brain fade' tends to rule nowadays, but, that it is possible to recover once, is immensely reassuring !
Thank you to everyone who has contributed, especially Jhieminga, and apologies for being slow on the uptake. The 'roundabout' can continue untenanted !

I am tempted to leave the 'pooter' permanently switched on, and programs running