Help clean this mess up

[C.A.R.]

Serviced the car at the weekend and typically on Thursday the boost gauge stopped reading so I went to investigate that too.

Turns out the previous owner was no stranger to 'bodging' things.

Is this a normal location to tap for a boost gauge?



Seems just a little bit inaccessable.

Added to that the actual nipple has snapped off quite low down -



So I can't get a vacuum hose on it to take a reading.

The intake elbow was done by what some people consider to be a pro on these forums, so I'm not going to name names, and who am I to know that it's not the 'done thing' on a HDi. It just seems a little bit mad.

Continuing on from that, I knocked another vacuum hose loose from the bulkhead, and I have no idea what it's for -

(look towards the brake pipes towards the back)



Which lead to this (the shorter section of rubber hose with the blue tape was loosely fixed over the end)



This has a rusty nail in the end of it, pressumably acting as a bung?



Then over by the solenoid-looking-thing by the brake master cylinder I found another professionally blanked vacuum hose -



Can anybody tell me what's what and how I can fix everything?

Assuming I need a new inlet elbow now? Is this a part which needs replacing when doing an FMIC conversion? As I could be tempted into having a laugh before selling this car on next year if that is the case.

I just want to tidy it up a bit