The most northerly roman fort investigated

[D B Campbell]

Do you mean an earlier Flavian date (than is usually assumed)?

No, I don't think so. (Sorry, I'm not sure what you're driving at.)

Or is Gask supposed to be post-Flavian now?

For those who are unfamiliar with Roman Scotland, the "Gask Ridge" is a military road linking the fort at Ardoch (at its southern end) to the fort at Bertha (at its northern end), via (in the middle) the fort at Strageath. The same road was used by Flavian and Antonine armies, and the three forts have Flavian and Antonine phases. (The forts beyond Bertha -- of which Stracathro is the northernmost -- are Flavian and show no signs of Antonine re-occupation.) At some stage, the military road was dotted with watch-towers, which are taken (by some) to be the hallmark of a "frontier"; they are universally (almost universally: I am a sceptic) accepted as Flavian. Hence, earlier than any comparable "frontier" (military road dotted with watch-towers) on the Continent.