FireProofing Party Wall in mid-terrace

Hi All
I'm just in the process of selling my property which is an old (1890) Victorian mid terrace house. The survey from the Purchaser has flagged up the party walls as being incomplete and that the sale cannot proceed until the wall is completed (due to Fire regulations).

So essentially I need to fireproof the party wall. Most of it is built from brick but at the ends where it is very difficult to get to the bricks stop short of the eaves. Firstly I'm assuming that the bricks should go right up to the end?

My question is what would be the easiest/quickest way to resolve this whilst keeping the surveyor happy? I've been told that cutting/wedging a fireproof foam board would be a good option and then seal around it (Rockwool Ablative Coated Batt). More bricks/mortar would be too difficult. Also putting in plasterboard would be very difficult (at least for me).

What do you reckon - I've included a picture so you can understand what I mean.

Thanks
Liam

ps I've filled in the big hole that you see with Thermalite bricks and mortar.

Ta

Liam,
If you are happy with Thermalite bricks and mortar, can you finish job with those?
Similar method was done here:
https://www.diynot.com/diy/threads/loft-firewall.128222/
and here:
https://www.homeownershub.com/uk-diy/installing-fire-break-walls-in-loft-447121-.htm

BUT as it is the 'surveyor' that you have to satisfy, ask them FIRST and before you start if "Thermalite bricks and mortar (or whatever others suggest) will meet his requirements".
Otherwise you might build something that does not satisfy them and they will not signoff.

Also make sure you tell homeowner on other side as likely to drop a bit of mess onto their side.

Also, from memory, "cutting/wedging a fireproof foam board" is NOT suitable. It is something like: wood frame, on which fire-plasterboard (red) or two plasterboard are applied to both sides of fame (your side and neighbors side), seams filled, screws covered. For small area liked that I wold use bricks and mortar.

SFK

You can't just wedge a fire board or anything as you wont be preventing fire spread from both sides, and there is nothing to stop the thing falling out in a fire situation.

It's bricks or blocks in mortar, for small gaps like that. Timber frame and fire resitant panels on both sides for larger gaps. You can't use bare plasterboard either.

ok - thanks for the advice. Block & Mortar it is then. They essentially said we just need to fill in the gaps.

The issue is that gap (x4) is a bit of a nightmare to get at. So essentially I will be lay flat on boards + added to that my rubbish mortaring skills.

I'll see if I can get someone in I guess - although is this the type of job most builders would run away from. It was like working in a coalmine up there the other day... hot & dusty.