The small 3.2mm id pipe that links all the injectors and fuel line on the diesel engine to return the unused fuel back to pump.

Just connect them together and see how it goes if no more leaks then you have sorted it and can leave like that or alter pipe work to reduce possible leak points.

The throttle body heater can be bypassed its not really needed in our climate, that way it will never cause a leak again.

Those type of clips can be tightened up with ceramic tile nippers if any needs to.

The pipe from the turbo to the intercooler is known to delaminate inside restricting the pipe looks ok from out side but pipe feels squidgy mine did it fine when not driving but under load it made a big bubble inside that rather restricted the flow.

Its an electric exhaust valve actuator , a surch with google lens brings this up https://www.ebay.co.uk/itm/355122805930

This is the part number for the Gates pipe, GATES 3225-00070 i often put a small cable tie on the end pulled up tight once in position but the cheep pipe still seems to sweat through the pipe. theceep stuff is almost a six monthly service item :(

i have just fitted two of those pumps to mine and my mates caravans and they work fine as they are, we were sick off the outboard pumps you drop in the barrel and cost £60 the new pumps were £20 each of jeffs emporium . we have to not open the tap so much or we will run out of water to quick...

The uk mains is a lot higher than 1 to 1.5 bar most mains is about 3 to 5 bar often with a pressure reduction valve, at 1 bar all these megaflow systems and combi boilers would not work very well at all, i have seen over 10bar blow me gauge of the tap.

A common leak item is the the throttle body heater which can be bypassed from the system if needed.

You should be able to unbolt the actuator vacuum body of the turbo with it still attached the the waste gate arm then you will be able to see which bit is the restriction unfortunately its probably a turbo off job but then its easier to work on .

The waste gate opens to stop the turbo putting to much boost out i believe they run at 11psi it dose not work on a set revs it works on pressure in the intake set up so is load and throttle sensitive, ie if you suddenly lift the throttle having been on full chat it will let some of the exhaust...

Ther is a company on fleebay that will for a fee send you the picks off the different lock nuts with the code number for you to match up you just have to remember your looking at a reverse image.

I would say it probably ticks over a bit smoother at that speed

+1 to glow plugs But get good ones beru are good and oem