CR-V RD9 2006 UK 2.2 Diesel - Intermittent Crank No Start

[Goonersman]

I'm trying to fault find a 2006 RD9 2.2 Diesel CR-V.
Intermittent crank no start.

When working (i.e. crank and start) ignition is switched on a range of lights illuminate on the dash, including EML and Glow-plug light. After 2 seconds, glow plug and EML go out. Turn key to start, Engine cranks and starts.

When not working (i.e. crank no start) ignition is switched on a range of lights illuminate on the dash excluding EML and Glow-plug light. From this initial position, if I turn key to start, engine will crank but not start.

Turning ignition off and back on again repeatedly (1-25 times) will eventually see the correct EML and glow plug light briefly illuminate and the car will then start.

Code scan shows 1 DTC. P0602 "Control Module Programming Error" but Googling suggests this can be caused by wiring faults.

I've located the ECU (left side footwell). There's no obvious damage/moisture/corrosion.

Thinking the issue might be glow-plug related, I've swapped out the glow-plug relay, located adjacent to the battery. Removing the relay causes the fault condition. i.e. with the relay removed, I get no EML and no glow-plug light on the dash. The replacement relay (ebay Item ID: 196059010011) behaves just the same so unless I've been really unlucky and bought a used relay with the exact same fault as the original, I think the issue lies elsewhere.

I've pulled various relays in the underbonnet fuse box and also those under the dash but all test ok.

Any suggestions for testing/diagnosis gratefully received.

Thanks

[Goonersman]

Testing update. 
I temporarily removed the ECU.  With the ECU removed, the dashboard lights are the same as when the fault is present.  i.e no EML and no glow-plug light.  
This leads me to believe the root problem is with the power supply to the ECU.
I rigged a test lamp to 15A fuse 17 in the fusebox near the steering column.  I belive this is the fuse for the ECU supply.  This fuse is live when the iginition switch is on, with or without the ECU installed.  The fuse is not live when the ignition switch is off.

Question:- is the power supply to the ECU (fuse 17) switched via a relay? If yes, where is this relay?

[Goonersman]

I've sent the ECU to ecutesting.com

[Goonersman]

£335 well spent. ECU repaired by ecutestingdotcom.  Car now starts on the button.