The trick, it seems, is in the mix of chilis. A lot of sauces I have read use capsicum peppers and tomatoes for body but I find that they meddle with the sauce too much. I prefer to use meaty medium heat chilis and lots of them, like a kilo of them. I add to that minced Birds Eye chilis and some Scots Bonnet too. That delivers the heat. Minced ginger, a little lime rind, coriander seed and some pepper corns for flavour and some whole cinnamon for aroma. White vinegar and jam sugar make up the rest of the mix. Heat it, reduce it, let it cool and bottle it. It really works.
If this batch works out OK, I reckon I have got it sorted. Next trick - the perfect 'brown' sauce.