To be honest although the op is not quite there yet, I rewired oro place myself and I can see where he's coming from although he has a few unanswered questions and is being defensive rather than open.
Although I'm not qualified at all, I spent some time researching, bought a book on domestic wiring, another on I&t. Then I asked questions until to make sure I didn't get flamed for not knowing anything!
Then I get the dno to replace their iron age cutout and the supplier to add an isolator switch then I set to work.
The main areas of uncertainty were that I bought out of calibration test equipment and I had to make my own tests up to check them. Which was not possible for the rcd tester.
Also I didn't have the experience to know the best way to split into circuits etc. I think I ended up with a few too many.
Is it safer? No one can say for sure, but the previous I dated to the late 70s (t&e but no green goo, wood framed wylex board in brown, earthed lighting circuits) plus plenty of DIY bodges and high loop ratings on both rings. Low it on the ground floor ring due to damp jbs under the floor. Random exposed chock blocks removed. No water bond.
Now it all tests out correctly, everything is still in safe zones, RCD protection. I'm happy that it's safer.
Also bearing in mind not all professionals in any field get it right all the time. I've counteracted my extra chance of making a mistake by thinking harder about it. Would a pro have done a better job? Good question. If it was someone on this forum, yes, because you lot are here to further your experience and care about the trade. But I've seen electricians who just want the money (you call them Electrical Trainee right?)
I do pay a highly recommended relative of a friend of a colleague to service the car. Last time he left the maf unplugged and the air filter box disconnected from the manifold, and told me the check engine light was on because the MAf was getting to the end of its life and would probably need replaced soon. He had replaced a bulb in that area. When I got home I realised it was all half disconnected and put it back, then when I asked him he swore blind sometimes there's a back pressure in old cars and it causes such an explosion that it pops it all apart. So yes it's sometimes worth spending the weekend doing a service yourself to save 40 quid.
Not trying to wind anyone else up, just two sides of the coin.