This is different to the problems arising on the other thread, although superficially it is similar.
Cavities in concrete construction are ventilated by default through the weep holes above the heads of opes. they are not intended to be fully vented per se
Timber Frame construction has weep holes as described above, but it also has vent holes below the DPM at ground level and at the top of the walls just below the eaves.
These are intended to fully vent the cavity, from below the sole plate to just below the eaves, to carry away moisture that may have condensed on the outer surface of the building paper used to face the outer surface of the timber frame/inner leaf.
Timber frame construction from say the mid-nineties to the mid to late noughties are not usually built with sealed building paper, but in the last few years the issue of wind-proofing the insulation layer has arisen as knowledge of building physics in the area of thermal performance has improved.
Given that the services are usually inboard of the quilted insulation I fail to see where the wind is coming from and wouldn't be too concerned beyond sealing the penetration.
Gaps between windows internally should be sealed, but externally these may be a form of intentional open joint detail - I cannot determine this remotely.
Downlighters are a difficulty, since they usually penetrate the ceiling which contributes to the 30 minutes fire resistance of the construction.
Under the attic they breach the vapour check designed to limit the migration of water vapour in the air through the insulation above.
If they are covered with insulation in the attic they can be a fire hazard, if ventilated, they are a cold spot when turned off.
ONQ
[broken link removed]
All advice on AAM is remote from the situation and cannot be relied upon as a defence or support - in and of itself - should legal action be taken.
Competent legal and building professionals should be asked to advise in Real Life with rights to inspect and issue reports on the matters at hand.