Thanks for that Gulliver, this incident happened a long time ago, before all those lovely complaints procedures, ombudsmen, citizen's advice centres and financial regulators etc, so it's outside the statue of limitations I guess (about 20 years). Even if these did exist then I wouldn't have known about them.
If it happened now I'd know what to do. The reason I posted my original query here was I was curious as to how they got away with it in those days which I've found out through this forum and being older and wiser and also thanks to AAM and other websites (no websites, nor microsoft then either) citizens are empowered. Also from the replies I've garnered that it actually could and does still does happen to people today.
Actually it was a very good lesson to me for I've had a lifelong aversion to banks since (and other powerful institutions) and I've never banked, nor will ever bank with the two banks involved.