Yesterday I went back and fitted the stove all over again. I wasn’t happy with the way the flue was installed, even though it was fitted the way it was designed to be.
The single skin stainless steel flue pipes, fittings and caps (chapéu) on sale here aren’t the most ideal flues from the point of view of efficient stove operation as the thin metal leads to rapid cooling of the combustion gases, causing condensation of water vapour and creosote accumulation at an accelerated rate. I’d already swapped my initial choice of 130mm pipe for 110mm before installation to increase draw and flue temperatures, but the nature of the pipe is such that 20mm diameter probably doesn’t make a massive amount of difference. (Though what do I know? I’m not a heating engineer.)