Has anyone had cavity wall insulation on a Victorian house?

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We're due to have it free through a government grant but having read stories about damp and condensation I'm starting to worry about it. Ours is a late Victorian detached house and we've been told it's suitable.
Has anyone had cavity wall insulation on a similar property who can tell me how it went please?

There wasn't much left of the stuff someone put in here, just bits of white fluffy stuff which went to dust if you touched it. Some areas the householders either got fleeced and it never got put in, or it may have been badly mixed, as there is just nothing. I don't think we'll miss it. And it made a right horlicks of the bricks- though the moron who used too thick a cutting disk to remove the old mortar when they repointed (with the wrong mortar, naturally, so I now have to get it all out again) added their malign bit to that as well.