If it ain't broken - don't fix it
Andy suggested it may have been turned 180degrees but the paver patterns don't match either way round
Don't remove the pavers (you'll never get them back in as neat as they are now).
Simply lift one end of the cover and drag it far enough to peer inside but...
To some extent responses will depend on the type of lamp holder ie E27 vs B22 and whether the socket is plastic or brass
With B22, both pins are fully recessed so the chances of making contact with either is slim, unless the bulb globe shatters
With E27, if wired incorrectly, the outer screwed...
Tapsplitter, like this.
You can make your own in the form of a paddle shaped out of a length of 18mm plywood say 75 x 200 Cut out a slot that will allow the paddle to fit over both tap body and spout. You then use the wooden paddle as a reaction lever to counter the torque of the spanner...
Why does the platform, that the sink sits on, project so far in front of the cabinet line. I think things would (or might) look a little better if the platform was recessed slightly behind the line of the cabinets. I'd also suggest you get your cabinet maker to manufactire some filler pieces...
Those air bricks on the house wall are there to prevent the house floor joists from rotting by allowing free movement of fresh air - ie they should be able to 'breath' fresh air
You'd lose all it's stregth if you bore enough out to accept the previous c0ck up.
I suggest you have 2 options ;
a) cut into the wall and correct the piping problem so's the elbow is sunk below the surface or
b) fit 10mm sheet of whatever over the complete wall so's the elbow ends up 'buried'...
You need to include the 1st floor plan to illustrate if any of it's walls are supported by the section you wish to remove.
That crack running in front of your hand is interesting as there has obviously been some load on the block