Delbourt wrote:

Thank you for detailing this and the clarity.
As I will probably attempt to renew the coolant hoses this is very useful information for me.
I am a little puzzled why there is a need to remove the air hose for the additional bleed. Is that to aid access or something more fundamental?

As I read and it and try to ensure I have all the detail in this procedure can you also clarify the following please?
After completing the initial bleeding steps and allowing the engine to cool experience suggests that any residual air collects in cavities that can be vented by releasing the bleed screw in the water rail. Is that correct?
Have I understood correctly that the additional bleed is performed without starting the engine? 
How long should it take to release any residual entrained air? In other words how much should I expect to have to top up the header tank please?
 

You do not need to remove air hose if you can reach bleeding point on coolant rail. However I doubt you will be able to reach bleed point on coolant rail without removing the air hose.

Yes, additional bleeding allows of any residual air from the engine to be released this way. It is done without starting the engine. How long - until you have constant flow of coolant, without interruption of potential air. If you see that header tank starts to empty, do not allow it to go lower then MIN mark. You need to top it up to MAX mark, and there should be when whole process is finished.

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