I made this with Pussers Navy Rum (so cut back the quantity to 45ml as it's 55% abv), Select and oloroso.
VERY impressed - the rum and sherry are very clear at the same time, the whole thing washed over with a gentle bitterness.
I'd have a second, but I'm a little frightened of it.

Fantastic cocktail. I love the original recipe, but also I make my riff with Spanish brandy and is a totally new experience.