On a new build, the answer is a straight yes, because you would position the brackets in exactly the same way as on a battened roof. On a retrofit, when you are replacing the last course of slates, you can’t access the nailholes, so you would need to use the HallHook. On a battened roof the nail holes are determined by the battens. On a sark boarded roof, the nails should be in the right position but they could be in a different position.
If the nails are not in the same position on a battened roof, then the HallHook can’t work effectively as the lap could be compromised.
Note: The hood on the SolarFlash® has a depth of 40mm. The Bracket should sit within the hood. If the Elbow (the first bend after the fixing plate) is greater than 40mm it will not fit within the hood.
Either the bracket needs to have an elbow of less than 40mm OR you would need to find the rafter, cut a hole in the sark board, exposing the rafter under the sark board and attach the bracket directly to the rafter.