Well this has turned out to be much less boring than I expected!
Consider this:
(1) PPrune Radar, you suggest that Manch SID tfc should be on the RPS, but why should anything UNDERNEATH be on the RPS? It's not under a TMA or CTA so surely if above 3000ft they must be on 1013 if IFR (with MSA here 3100ft), and should be if VFR?
(2) To add to the confusion, Hawarden's 05 procedures go through here at 3100ft on the Hawarden QNH so whatever you have on your altimeter you might well meet a Beluga going the other way.
NS