But as the circling area is defined as distances from the airfield (a sort of convex hull around radii projected from the respective thresholds), either you're inside the area or not...
The charts show the same circling limitations (066-->264deg) for all approaches.
From memory so please check;
The area to be excluded is clearly defined as you say. However, if the final approach area and missed approach area for the VOR overlies part of this area, then obstacles in this overlap will still have to be taken into account despite the fact that overflight is not permitted by the restriction.
Even if the restriction was simply no circling north of 08/26, obstacles north of the centerlines of each runway contained within the annex 14 approach areas and the final approach and missed approach areas for the procedure which are north of the centerline and within the total circling area have to be included.
In simple terms you have to be safe in terms of obstacles flying just inside the most northerly boundary of the final approach area and missed approach area which are contained within the circling area.
While pilots are thinking in terms of being 5 degrees off to the north from overhead the VOR, the final approach area will be a certain width at the VOR and diverge at 8 degrees. Thus really being only 5 degrees off after passing exactly over the VOR would not be at the northern boundary of the approach area in which obstacles are considdered.
There is the posibility of a pilot at the circling MDA being well north of the final approach track but still being contained within the final approach area for the VOR.
Remember that the VOR final approach area is expanding as one moves away from the VOR but the LOC final approach area is getting smaller.
Sit back and do a few simple math calculations based on the following principles for CAT C (ICAO);
1. Circling minimum obstacle clearance is 394ft with a lower limit of 591ft above the aerodrome elevation
2. The final approach obstacle clearance for the VOR final approach area is 246ft as it is for LOC
Missed approach obstacle clearance is a minimum of 98ft and then 164ft
You can play with the figures and come up with a best guess as to what the obstacle is causing and then look at the chart.
My guess is that the slopes of the hill NW of the airport are the dominant obstacle.
However, all that is simply guess work and I would be more inclined to err on the side of safety and use the more recent higher minima for all circling operations.
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As for TERPS, circling area is defined in "miles" and is much smaller than icao but the speeds are different and the minimum obstacle clearance is less. So not really the same thing at all.
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ICAO circling is based on 20 deg aver age bank or rate 1 whichever requries less bank and for cat C a TAS of 180Kt and wind of 25Kt giving an overall speed of 215 Kt combined with 20 degrees AOB for calculation of turn radius.