Hello everyone. First time poster, long time lurker etc. Will try to keep this brief but am looking for some guidance from the experts.
This is my first attempt at some home renovations on my first home so please be gentle. Limited DIY skills being a simple data analyst but learning as I go. I've started in our spare bedroom on the first floor which is my covid office. Cold draughts from under the skirting, particularly from the wall which looks out over the front of the property. I've been using posts within the forum and the excellent readinguk.org posts as guidance but wondered if I could get your opinions on how best to deal with a couple of specific issues I've hit.

Context: 1990 end of terrace 3 bed house. Block and Beam ground floor. Dot and dab plasterboard. Aircrete inner leaf. Integral garage... Can't think of much else but assuming I've captured most of the bad-house-bingo marks there.
So far I’ve had the cavity fully filled (60mm) with polypearl platinum eps beads and have been working on filling the loft with 500mm of insulation although I will be going back up there to address some of the penetrations.
I am attempting to do the actions listed in the following:
https://readinguk.org/draughtbusters/going-further/first-floor-void/
https://readinguk.org/draughtbusters/going-further/dot-and-dab/
https://readinguk.org/draughtbusters/basic-techniques/walls-and-windows/

Question 1: How best to fill an 8cm diameter hole within the aircrete block? I can see the outer leaf brickwork through it.

Question 2: How best to deal with a 20cm diameter hole which has both cables and pipework going through the wall and entering the roof space above our front door entrance and downstairs loo. The aircrete block is crumbling here and around half of the hole is covered in EPS beads from having the cavity filled.

Question 3: Between the inner leaf block and the ceiling/wall plasterboard joint of the room below there is a gap is a 2cm gap followed by a 28cm drop to the next aircrete block where I can see a metal lintel. Would you run gap foam around in a similar manner to the readinguk.org first floor voids article or would you attempt to put something down there such as insulation around the metal lintel?

I am trying to publish photographs of the above areas however it is my first time posting photographs on the forum.

Hole 2 - 20cm dia - cables and pipes running through to roof space above front door and downstairs loo

Been there already , not just you but millions like it and they are still building them

https://readinguk.org/draughtbusters/going-further/first-floor-void/

Thanks Tony, I am actually working my way through the steps within that link but it's more that I'm unsure of how best to approach the above issues I've run in to and was seeking some guidance.

Was possibly thinking:
8cm dia hole (1) - Expanding foam then carry on with the insulating board foamed over in line with the boarding between other joists.

20cm dia hole (2) - Attempt to bunch cables and pipework together through as they enter the wall. Use insulation board with a cutout for the penetrations to pass through, foam this to the wall and use airtight tape around the cables/pipes on to the insulation board... Will this work well? Should I use expanding foam in the hole given there's services going through?

Metal lintel - Poke wool insulation down along the lintel as best I can and then carry on with gap foam along the plasterboard?

Firstly, good on you for making a proper effort to improve things and all the more so as youre not a tradesman

Where you can see the outer leaf of brickwork from the inside there should be insulation beads. If the CWI came with a guarantee I would make a claim on the guarantee. That may initially seem over the top but when we made a claim a surveyor came out, drilled lots of small holes in the outer leaf of the wall then used an endoscope to check for full fill of insulation. He found many more areas of missing insulation than we had spotted looking down into the cavity with the edge of the roof stripped off. He put together a schedule of remedial works which was completed a few weeks later. Talking to the surveyor he knew from experience the areas that would have be missed and also by looking at the original injection hole positioning. Claiming on the guarantee was a very easy and productive process.

I quite like pushing fibreglass blob into big holes then foaming over the top of them and sticking board over the whole lot.

I don’t like tapes, they seem too temporary.

I don’t worry about cables in contact with eps, foam seems OK though.

Well done tackling it. Happy to look at more pics and advise

Posted By: DWHITEPhiledge, really interesting! I would never have thought of making a claim as I assumed the beads had just fallen out of any holes and that would be beyond the reasonable ask of a CWI installation company to compensate for.

If the 80mm hole is as you found it and youvev not removed any beads, then thats a defect. You can probably deal with that hole on its own but how do you know there arent more areas with missing beads?

With ours I estimate that we had 10-20% of our insulation missing. Very few places had the insulation to the top of the cavity and 2 corners had the insulation 2-3' below the top. We had internal condensation issues in both those corners and its no wonder with just a single brick between the room and the chilly winter air.

Make a claim and the surveyor should know exactly which areas will have been missed.