The reason you have been 'Criminal Record Checked' is to create jobs in Labour constituencies in Scotland, and to allow the government to impose yet another tax on aviation and other hapless industries.
The CRC is no more use than a quick scan of your birth certificate and a call to the local nick.
There is no possible justification for the treatment of flight crew by UK security operatives. If police officers can pass unmolested than pilots certainly can.
It's like living in East Germany.