IMO, the UK government is mortally afraid of being accused of not obeying EU laws, particularly those regarding competition. Helping Rover would be seen here as unauthorised subsidy, though a similar practice in France or Germany would be seen as patriotism!
Surely you've noticed that we allow the purchase of our companies by EU ones but that the converse is heavily discouraged or disallowed for one reason or another.
Another problem with our membership of the EU is our "gold-plating" of EU regulations, i.e. making them more stringent than they need to be. E.g. Human Rights legislation, mass closure of abbattoirs, the working-time directive that will cripple our haulage industry but has no such effect over the Channel, Disability Access Regulations etc etc
Anit-EU campaigners will say "look what the EU have made us do" whereas the truth is that the faceless bureaucrats in Whitehall have interpreted the law from Brussels in a ridiculously pedantic way.
Rant over.
