I agree you should not have it buried in the wall since access is needed. Try decorating around it somehow (i would have to see your setup for ideas).
Remember pipes should always be accessible in case of repair or damage.
Jonathan (London plumber and London builder)
I agree a 22mm trunk route would be your best option unless you want to re-do the entire plumbing.
go with plastic and see if it improves. let us know the results
Jonathan
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