could be the pics or my eyes but 1st pic bottom edge looks a tad like fibre glass raggy edge, have you had a wander with a simple little magnet.

Sorry not intercooler, I meant to say gearbox oil pipes, these go into the cooler at the bottom of the coolant rad, sorry for the misleading info.

The bolts that can break are the ones that mount the fans to the rear of the rad. And the ones that mount the brackets carrying the intercooler pipes. Usual amounts of release agent first should do the trick. If they do break they are nothing special to replace so don't worry, give it a go.
Don't ...

Geoff's correct, both screws are blocking the loss of vac or transfer to the next item in the pipework system maybe the solenoid has failed either open or closed, an applied 12 v supply to it will tell if the solenoid is operating.

I always start by doing a pressure test, if its not holding pressure it won't hold coolant.
The front and rear heaters can sometimes be an issue, airlocking. Check the flow through the heaters, sometimes they require a squeeze or two. Try to get as much coolant into the system as you can by ...

Check the vac pipes are all in good nick, (not split ) or left off, and the little green filter on the turbo pipe connection, these can get disturbed when doing the glow plugs.

What work did you have done?. Engine speed sensor at the front of the engine (crank sensor). May just need removing and cleaning, they can get oil on the sensor face and start acting up, or the wire needs checking, it's an easy check.

Do a search on the forum for 2 ltr exhaust manifold.
They are double skinned and can split on the inner skin, this can make a ticking sound as the escaping gasses get through the inner and hit the outer skin.

Yes, it's a lot easier. Just can be hard to get the pipe mountings undone as they rust and can snap, length of release agent usually gets em off.
May have to remove the battery and tray too. Good luck

Will miss the giggle, thoughts from us all here

All the best from us up here, hope to see you all when the sun shines again.

Oil gets behind the crankshaft sensor and messes up the reading.. remove it, clean the oil out of the sensor hole and wipe the sensor face .watch out for the O ring. Worth a cheap fix try.

Over the starter motor pipe. Check the other end where it clips to the heater system it rots away

Sounds like it wasn't bled completely when the pipe was swapped. Top it to the correct level when cold and see if it holds its own over a few local journeys.

The short rear one is for the sliding door side, so it doesn't rip it off when you open the door.