But have you actually checked for spark?
Just hearing "faint explosions" does not qualify.
You need to remove a spark plug, re-attach the plug wire and have a friend crank the engine over while you check for spark.

 

Assuming valves are functioning.

How many miles on the engine?

Could timing chain have skipped some teeth?
Open oil filler and look for valve movement? Not sure you can see the
valves that way.

Verify spark plugs are plugged on the correct plugs.

Need to know the history of this rover... And what was done to it.

 

You might try this

Have you tried the EKA code of 1515? I was able to use that on my 99 D2 to disable the alarm after replacing a couple of computers.

Quote:
The code is recorded on the security information card and is entered as follows:

1. Using the key, turn the driver's door lock to the UNLOCK position and hold in this position for at least 5 seconds. An audible warning is then emitted to indicate that the body control unit is ready to accept the code. Return the key to the centre position. It is now possible to use the key to enter the separate numerical values of the four digits that make up the EKA code.
2. Enter the first digit of the code. If the first digit is 4, turn the key to the UNLOCK position 4 times. Ensure the key is fully returned to the centre position after each turn of the key.
3. Enter the second digit of the code. If the second digit is 3, turn the key to the LOCK position 3 times. Ensure the key is fully returned to the centre position after each turn of the key.
4. Enter the third digit of the code. If the third digit is 2, turn the key to the UNLOCK position twice. Ensure the key is fully returned to the centre position after each turn of the key.
5. Enter the fourth digit of the code. If the fourth digit is 1, turn the key to the LOCK position once. Ensure the key is fully returned to the centre position after each turn of the key.
6. Finally, turn the key to the UNLOCK position and back to the centre position, a double bleep will indicate that the code has been entered correctly. A single bleep indicates that the code has been entered incorrectly.

The EKA code will not be recognised if there is an interval of 10 seconds or more between key turns or if the key is held turned for 5 seconds or more during the procedure.

In some system configurations a successful EKA code entry is indicated by the audible warning device pulsing twice for a period of 50 ms on, 200 ms off. The theft deterrent LED is switched on for 1 second, all doors unlock, the alarm disarms and the vehicle is remobilised allowing the engine to start.

If an incorrect code is entered, an audible warning is emitted and the procedure must be repeated. Up to a maximum of 10 attempts to enter the code is possible. After 10 attempts, the BCU will not allow any further codes to be entered for a period of 10 minutes.

 

History - Engine suddenly stopped running.
What could jam the camshaft and make it break?

Has spark.
Has fuel.
I bet some or all valves are not operating.
Googling I see that the Discovery 2 has a camshaft position sensor also.

 

Here is the crankshaft position sensor - which you replaced..
So if the camshaft sensor is dead - I bet this is fatal to the ECU getting the timing correct.

Yes, I bet this is your problem.
Probably the camshaft sensor figures out where the camshaft is - which determines WHAT cylinder to fire.

The crankshaft sensor determines WHEN to fire the spark..

So, in essence, your engine is "LOST" as it has spark, but is not firing the spark to the correct cylinder.

I bet horseshoes to hand grenades this is it.

Here is the crank sensor you replaced:

 

Regarding the Camshaft sensor - I had NO idea that our D2 engines even used one.
Great to learn yes?

 

So, history - engine quit running.
Camshaft sensor quits - engine gets LOST and quits running.
Via the history you provided - this should be the problem..

 

ALL fuel injected gasoline engines have one, that is what tells the injectors when to quirt.
Even a '94 DI with a dizzy has one.
They almost never fail, at least on the DI.
This could be his problem.

 

haha,
Spike, I bet you are right..
I never knew we had one.
But, yes, it makes sense.
I bet he will be on his way.

 

Our engines will run with a failed cam sensor, its only function is to show the ECU top dead center which it then uses to set the timing for the injectors.
My money is on a failed cam or timing chain and would suggest a compression test and possibly a leak down test.