I'm afraid the only person here who is demonstrating any ignorance of foundations is yourself.
If you say so.
Weirdly I was never called back for a collapsed porch, cracked walls, etc.
Must have been pure luck...
To build on 200mm concrete you need solid ground, not available anywhere in the london area as far as i know.
Maybe in the rocky montains of Scotland, but surely not around here.
That porch that collapsed had failed fundations and the "master" was suggesting building on even weaker ones.
Read the thread.