Can anyone explain the regs for chimneys adjacent to a neighbour please, we are getting gassed

Yeah I'm fairly sure that's against regs.

I’m a stove fan, have two of them and I’m really shocked at that installation, the chimney terminates way below the house roof pitch and smoke is challenged to disperse.

Smoke and smuts are getting into your home, The. smell is only part of it, not nice. Get onto the EPA and local CoCo environment section.

That chimney looks like a health hazard it's so low.

However Found the EPA just as useless as the county council when I had to deal with back yard burning from the same premises near me. Persists to this day.

If you can cant get any positive outcome with the county council contact the EPA they say. So what does the EPA do ? Write up a lovely report and sent it to the county council that did FA in the first place.

Do you not draw your diagonal from verge level opposite flue (edge of lower structure) to higher eaves level (edge of vertical structure) - then draw your vertical intersection 2.3m off the line of the higher structure? Just checking my own understanding of that setting out!

Difficult to tell without better photographs or dimensions whether the flue falls inside or outside that zone. What happens when the flue is outside the critical zone but still causing a nuisance?

NO wonder He wept

Have you just arrived here from Arrakis

This is crude and rough but lets see what the experts think here.

Angle is 30 degrees so it goes vertical at a height 4.445 m above the roof of the extension, crucially 2.3 m out from the wall of the 2 storey house so OP, we need to know two things

How far the flue is from the face of the 2 storey and your estimate of the flue height above the eave of the single storey.

If you post that I will redo the diagram.

My view is it does not comply so you file a complaint an observation with the LA

I agree , that was my take as well but this test might be a bit more conservative