Watched Giles throughout his England career never thought he was that great just the best of the rest that was around at that time.
If you read my original post, I didn;t argue that he was a great bowler, merely that he was the right spinner for that England side. They had four attacking, wicket taking quicks, so needed a spinner would could bowl dry whilst picking up the occasional wicket as batsmen sought to see him as their escape valve. He did that very well - and did in fact turn the ball more than most people expected when on a helpful wicket. A similar analogy would be the way that Paul Harris proved useful for South Africa.