Questions... Morphology? Longevity? Water pipes?

I had a very very small pin hole leak at the engine end about 5 years back in the engine bay. I put a silicone pipe over the top with jubilee clips either side and not had a problem since ?

So is there no way of threading up through engine bay if in two sections/ same on way out if cut ?

Also are the stainless ones readily in stock.

Saw a thread around buying these in bulk a few months back but missed that boat

Just seen a pic of the route it takes and why it needs engine out !!