Thanks for your feedback DampeS8N. I wish I had specific tags available to do searches in, which would have made the whole job a lot easier, but all I have is a set of content in which the replacements can't be made within elements such as links and headers, plus not within any HTML tags.
I've managed to sort the issue of not performing searches within HTML tags, but have not been able to find a way to express not to search between </a> - </a> and <h1> - </h1> etc.
I've managed to sort the issue of not performing searches within HTML tags, but have not been able to find a way to express not to search between </a> - </a> and <h1> - </h1> etc.