Did some testing this evening, and I'm happy with the results. Pressurised the system to 5 bar (need to buy myself a proper compessor for higher pressures). Was a bit concerned whether the 5/2 way valve would work properly, its miniscule compared to the rest of the system was worrying me! but I confirmed that it does not affect in anyway the flow through the system.
I can now turn my attention to the rest of the build.
Video in action
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