old boiler vent hole left open on internal wall

[advice-please]

We have had a new boiler installed, but we have a number of outstanding issues. One issue is that they had to drill a new vent hole. The old vent hole has been bricked up on the outside wall, and completed very well, but on further investigation at the top of the new boiler, no attempt has been made to fill the inside wall. The inner wall has an approx 100mm diameter hole remaining, together with an unsealed gap to the dry lining. Although the installers have said they will rectify this whilst doing another visit, my concerns are that if I had not got on a step stool to look we would not have been aware of this. Is it safe to be left like this from a fume point of view, and more seriously from a fire safety point? Having seen this, I then peeled back the rubber seal round the new flue see photo. Should this gap be backfilled with a mortar mix around the flue, rather than leaving a large gap which is cosmetically sealed by the rubber? Also if a job is completed and left like this, does this look like work that has been completed by a professional company?

 

[John D v2.0]

It's the outside seal that is important, there should be no possibility of fumes entering any void or opening into the building. Regarding the inner leaf it should really be filled for insulation reasons and to prevent draughts from the cavity

 

[tony1851]

Sure, the old hole should have been boarded over; can't see any issue with the sealing of the upper hole - that's what the rubber's for.