Although 1 and 2 seem OK 3 and 4 does not follow what one would expect. “Electrical, Wiring a ceiling rose” in projects section shows what we would expect to see. And “Electrical, replace light fitting” shows how the cables should be routed above the ceiling. In the old colours so Red = brown, Black = Blue, normally no PVC on earth and a Green/Yellow sleeve is added after stripping back. Because the ceiling rose acts as a junction box as well as connecting lamp it’s self it is common to connect the browns to the lamp in error where they should only connect together.
But since your wiring seems to be non standard it is impossible to work out what is wrong without being on site and testing.
Sorry to say “As built” plans are rare with houses and I would not think the builder will help other than sending an electrician. One thought could 3 and 4 be the same cable as two brown and earth cable is available and is the correct cable to connect the switch up with although rarely used. In which case one should go to local lamp and others (all browns left) join together in loop connector.
Will give that one a try Eric....did speak with builders yesterday as a few other problems still need fixing so they are going to send someone...seems ho I've been waiting over a year for the other bits I'm not holding my breath!!
I'll let you know how I get on and thanks for taking the time to reply.
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