Many thanks for your advice, dddd.

First, my new Presta-equipped tubes have shipped now so the die is cast .

I would happily use a hose if I could find one was compatible with my Zefal pump but I am not sure if that is possible. I'll do some more research on that.
I think your suggestion of reinforcing the arrangement with a square of tape is promising and I think that is what I will pin my hopes on.

Thanks again!