Fair Isle's major worry is wind. If it gets above about 20kts from Sheep Rock or the hills to the N then the turbulence out classes the controllability of the a/c.
Foula has a similar problem but the wind limits start at about 15 kts if it's from one of the adverse directions.
If you liked Fair Isle, you would love Out Skerries.
It's 381m, downhill to the E & has a fence about 1 or 2 m from the Islander's wingtip if you're at the RWY edge. The approach to 09 has a ridge ~50m prior to the threshold that intrudes into a normal approach profile.
It then drops into a steep sided gully between it & the threshold.
There's no undershoot area in either direction.
It's particularly 'interesting' at night because the ridge isn't obstacle lit unless couple of battery powered roadwork lights are placed on it...
There's a few other cautions, but they're the major ones.
