Sadly, because they have nowhere near here to relocate to, or I'm sure they all would!
The guys at Signature are all nice people, I'm sure it's not been done out of malice towards the club, just a change of direction now that the airport has expanded and become too busy. Even the commercial helicopter companies struggle to get circuit training done without huge delays, hence the investment in new simulators up here.
For me, it's worth the drive to Dundee, only £140 per hour to hire an aerobatic grob, and no landing fee. Amazing that a little city like Dundee has had such a successful flying club for so many years. I guess partly due to a smaller GA airport, no controlled airspace and also the air cadet contract which has kept the money flowing in. If only Aberdeen had a suitable alternative airfield near by, with the money up here I'm sure it would do okay, just look at how busy HJS helicopters are at Peterculter.