Cavity insulation, 1930's semi, suspended floor + airbricks?

Considering cavity insulation for our 1930's semi. I asked before about some of the issues with it - and someone mentioned sleeving the airbricks we have.

I don't know the exact constuction of our walls/floors - but we have airbricks on the outer wall, but none visible on our internal walls. I assume that the airbricks only provide ventilation to the cavity, AND under the floors.

Would the people installing the cavity insulation (in my case,

- a Guildford Borough Council scheme which is a re-branded CEN service - Creative Environmental Networks, a non-profit organisation just remove the existing airbricks, and replace with sleeved varieties? I assume that there will be an corresponding access opposite the airbrick to provide access to the under floor area.

Is there any chance they could end up pumping it all into the wall, and into the under floor area, filling it up?

Thanks for the info - I'm just a bit paranoid about the problems with getting this done - don't want to get any damp problems - just want warmer walls, and less heating costs!

Thanks

D