Failing heater water bypass tube (EF18663A)

[peterljohnson55]

Gday guys and gals,

CAR: AUII Fairmont Ghia 2001, 4.0L; Located in Newcastle, NSW.
PROBLEM 1: the bypass tube is rusting at its connection to the back of water pump. Probably could snap off anytime and I could lose all coolant very quickly (then the engine suffers Death by dehydration).
PROBLEM 2: apparently this bypass tube (EF18663A) is no longer stocked by Ford and I cant find a new one anywhere. (Item advertised at Covs Parts n/a; cant see any on ebay)
PROBLEM 3: 2nd hand tubes do not seem a good option.
PROBLEM 4: Apparently it is a cow of a job and expensive to replace such a low cost part. Is it just a matter of R/R the manifold for access? One person said 'engine out'. I presentlyhave the transmission out if that helps.
PROBLEM 5: As you can figure, I am no mechanic.

Can you please help with advice on any of the following, or any other matter you see relevant ...

A) location of new tube to purchase.
B) wisdom or not in using 2nd hand tube.
C) alternative route for home-made tube.
D) prospect of a modification to BA, BS tube (AU318863) as suggested by Ford Spares interpreter.

Would really appreciate your guidance here.
Thanks.
Peter.