MNPS Airways
You definitely need NAT MNPS approval to fly the airways in MNPS airspace. There's also only one kind of approval, there is no halfway step.
T9 and the northern routes like G3 and the "Blue Spruce" routes (the dotted lines on the Aerad NAT chart) all have VHF coverage, with the exception of the two that clip the Shawick OCA. HF is not required except to fly these two routes. As I understand it, HF is still a requirement for ANY penetration of Shanwick OCA.
T9 and the "Blue Spruce" routes can be flown with only a single Long Range Nav (LRN) system (if your #2 IRS has failed, for example). T14 and T16 require dual LRN's.
Hope this helps.