As said up-thread the red dot is excellent at a fixed range and can be used whilst resting your trigger hand on your face giving stability. It works in sub-optimal light too.

I just noticed that both the rear and front iron sights are visible through a tiny gap/hole under the scope mounts, which just happens to be bang-on at the centre of the rear iron-sight aiming point

This with, as before, the pistol supported by my face at the rear. No chance of any focus on the rear sight, but it doesn't matter. The rear scope mount against the rear sight becomes a peep-sight. The front sight is not in focus of course, but good enough for government work.

It bloody well works!

I have two sighting methods now for my first cheap PCP pistol. The red dot for good precision and fast aquisition at a known distance, and open / iron / aperture sight for a more forgiving tolerance of variation of range. Both methods using my head as a stablising mass for the pistol. This due to the iron sights being much closer and much more aligned to the axis of the barrel.