Warren

I think you have to some extent answered your own question.

Any off the shelf book that is generic is likely to need to contain an excess of the variables that need to be considered in your own specific circumstances.

You are probably better served with one or more bespoke sets of documentation. So, as example you might have a PTW document for high voltage working and another for entry into confined spaces. There might be occasions when you need both.

But, if you try and cover all the variables on one document, it is likely to become so unwieldy that it ends up being a tick box exercise and fall into disrespute.

Do you have contacts in organisations doing similar work to you that you could approach for their thoughts or even a collaborative approach that suits you and others?