I imagine that the primary radar head is going to be at Inverness Airport, and that the SSR will be either piped in to consoles at Inverness, or it could easily be remoted to Aberdeen.
If the radar head is at Inverness, they then have the option to contract it out to NATS for 3 years until they have enough trained atco's at Inverness to fulfill the task, then pipe in the SSR.
As far as I am aware, HIAL have no radar atco's, so either way they're in for an expensive few years.
If and when it eventually all located at Inverness it would be a groovy number as HIAL pay near enough the equivilant of NATS rates, and it's a nice place to pass the time of day.