There were similar issues with nav aids over the Atlantic and with 8.33 kHz radios.
In the latter case some aircraft that did not usually fly in upper airspace, Tornado GR 1 for instance, did not have to comply whereas the Tornado F3 did. Although there may have been a State exemption the rules were actually binding.
On nav aids I think the height was either 270 or 290; Nimrod had to be fitted with Omega to permit flight in the upper air structure. No exemptions.