crawl space

Hi! We have recently purchased a 1930s built house in Greater Manchester. There are a lot of issues that we are discovering after the purchase. Damp and condensation are the usual culprits. Recently we found out that there is wet clay in the crawl space under the dining room. And it seems...

Please can i get some advice how to cut a small access door in this wall. The photo shows the back of my house which has a crawl space below the airbricks. I want to cut an access hole approx 50cm X 70cm to the crawl space, the proposed hole is marked with green colour. The wall is two skins...