It should be remembered that there are significant areas of Scotland where two way with Scottish is not possible unless you are at a significant height above the terrain.
From memory over the Firth of Lorn its quite good - but a few miles inland and it's impossible unless you get above FL 5x something.
At the end of the day in any CFIT incident radio contact is not even a 'nice to have'. For any of the other failures a broadcast on 121.5 is more likely to get attention.
Scottish frequently find they cannot maintain two-way and are probably quite used to aircraft 'disappearing', I suspect only if they suspect a problem would they try and track down the aircraft. It is largely because of this that many pilots in this area only contact Scottish if they expect to be able to maintain two way - coming from the eastern side of Scotland I don't expect to be able to....