Nice work mate, yes give it a good clean and you should be good. Defo look for the bolt but i know what you mean. Things get lost very easily in that engine bay. I have a magnetic pickup tool which really helps
Never heard of this before but because your car is under warranty it should be fine.
Redex will not cause that in my experience.
See what the dealer says and please do feedback. Hope you get it sorted
I had a massive whining noise and thought it was bearings. Sounded just like bearing. Upgraded my wheels and my noise was gone. So do check tyres before doing anything
I go from the side of the arch. I actually take the arch lining off a bit and just force my hand in to reach the bulb. They are a pain on the diesel with such a big engine block