Thanks Charlie and Peter :-))
Indirectly that part of the problem is now solved. I am most grateful. I have been working on this now for a long time ($DAYS or $WEEKS - I have lost count). I have to get it properly sorted out by the coming weekend at the very latest since my granddaughter needs her laptop for school.
The real aim is to get it working dynamically, so that it can connect to any wireless hotspot - tho' initially home and school would do! But festina lente. It will at least connect statically now without having to be reset every time I boot.
I solved it by finally getting rid of NetworkManager, which was not easy. It doesn't want to be got rid of. But I succeeded - and now the settings are taken from /etc/network/interfaces. \o/
I doubt that I would have got as far as I have for days, if not more weeks without your help. Charlie convinced me that I wanted to try the other avenue suggested and come back to that. ;-) You, Peter, convinced me to try another method. The driver was definitely there. According to the Ubuntu help files it just didn't work very well. But as I was convinced already that whatever happened NM had got to go, I came to the conclusion that I should do that first instead of second.
The rest is history, as they say. :-)
Let's just hope that the problems with DHCP were the fault of NM and not of the driver. ;-)
Lisi
