As a 25% shareholder the government cannot guarantee slots to LHR for 5 years, so why should any one else. I believe this is more political than economics. An election next year.
If the Irish government were so concerned about Aer Lingus and LHR connectivity; then why did they privatise the company and maintain only a minority stake.
They don't need the Govt's shareholding to control the company.
Time to buy it as once you past 50% you are in control.
Having 25% or more gives you no control in an Airline.