Uncapped Cavity Wall Insulation

Hi

I decided to go for polybead insulation for the cavity walls in my 60's built detached bungalow. The surveyor came round and said all was ok.

When the installers came round I asked them if the open cavity would be a problem. Initially they said that it wouldn't be a problem, since the top row of the fill would be 3 courses down from the top. Anyway they had a look in the loft and suggested that the since the glass fibre was right to the edge of the roof then there would not be a problem.
Now from what I can see from the BBA certificate for the product, the cavity should be capped with mineral fibre, before filling. I suspect that this is to prevent the polybeads forming a fire hazard in the eaves. When I pointed this out they decided not to proceed and to arrange to send out another surveyor to have a look.

I just wondered what common practice should be in this situation?

The other thing that occurred to me was that if the top 3 courses of the outer skin are not filled, add to that the inner skin, which is 5 courses higher, this would mean that the top 2ft (25%) of the wall would not be filled.
This is starting to look like waste of time.

Get an installer who uses fibre not poly beads

just buy some waterproof batts and stuff them into the top of the cavity providing a stop for the beads.

Thanks for the replies.
I'll not be using these people so will most likely use fibrre instead. However I'm still wondering about the wisdom of potentially having 3/4 filled walls.