A
They have placed them all around the house, the previous owner was struggling with damp issues and didn't have the knowledge to address them properly.This is a really early thread and I think the forum software changed around 2005 and it makes no sense.
The Schrijver System seems to be an approach to try to let a bit of water out from nice lime mortared brick walls after you have cement rendered and waterproof painted them. They take a brick out and put magic in there. If you are back to nice breathable lime mortar on the outside it should work way better than the damp proofing invention. Chop it out and bung a brick back in.
It would be interesting to see photos. I've never come across this system in real life.
While they are unlikely to fix damp problems, when you have the cement pointing and render and plastic waterproof paint and high external ground levels they might actually be doing a little bit of good. Less good than letting the whole wall evaporate water away, but more good than completely waterproofing the wall. The brown render might well be lime. Anything with green growing on it is much too waterproof.
What are your plans?