I bought a pattern one and it lasted 6 months, genuine LR one was cheaper.

Possibly oil drain tube?

A "tick" is also a sign of manifold failure.

P006A-00 is often associated with one or both inlet manifolds cracked which I guess would also give low boost pressure as air is leaking from the crack(s).

I would change the injector seals before you try anything else.

Genuine TD5 water pump and aux belt (belt for models with aircon) still in original packaging. Pump PEM500040. Belt PQS101500. Current retail around £250 the pair, will take £125 (cash only). Based near Cambridge, buyer collects or may meet half way depending on distance.

How old is your battery? A bad battery can cause this. Maybe go find a place that sells batteries and get them to test it.

You need someone with a code reader to diagnose the problem.

Firstly check the long hose which goes to the water pump. I though mine was the pump so bought one and then discovered it was the hose. I have a brand new genuine pump still in box if you do need one.

First thing you need to do is check the battery is healthy as a failing battery can cause those kind of problems.

I didn't have any diesel in the sump either, just virtually no acceleration, very poor starting and random cutting out.

I did, changed everything - loom, fuel pump, filter head, glowplugs and pipes to tank. All this made virtually no difference. Once the seals were done it ran really well until a tree fell on it in Storm Doris:eek:

Probably injector seals, make sure you use genuine ones. Unless you are very good with spanners I would pay someone to do it. Parts are pretty cheap and it's not a big job to someone who knows how to do it.

not sure if that might help?

I know of quite a few but most seem to be locked off for some reason. Where are you in Cambs?