Keeping your home warm / heating / energy crisis / insulation etc

I am about to spend a decent chunk of change on cavity wall insulation.
1970's property with nothing at all in the cavity.
Getting quotes for poly bead and adhesive fill

There are a few risks I am worried about

1. Damp and condensation
   
2. All the beads escaping when we replace the windows, for example
   
3. Having zero recourse should either of these two things happen
   
   

Has anyone appointed an insulation contractor to do cavity wall insulation for them?

What sort of accreditations should I be looking for and what certificates do I or building control need?