I still think Paul Nicholas was very clever casting for the role as originally described. He needed to be handsome, charming, charismatic for it to be believable that Kathy fell for him and was prepared to play dead for him. But, there needed to be a very dangerous man hidden underneath.
Paul Nicholas was capable of that - look at him in Tommy or Just Good Friends for the attractive side.
But the scripts weren't good enough and that dreadful backstory. I could just about live with him turning out to be Sharon's Dad, that Ted had happened to know, and then introduce Kathy in SA to the man that had got Carol pregnant 30 years earlier. But they shouldn't have mucked round with the established circumstances of how and when Sharon was adopted by Den and Angie, that he was part of this posse, that he lived next to Ethel as a kid etc.