As the mirror is the only major paper to run this none story it does feel like they have an agenda.
I agree xylyx, they are running so many many stupid stories it does feel like they are set on damaging Merlin's reputation. There is speculation that this is to damage brands (and The Sun) who use Merlin promotions, and I see that as very likely. Overall it's just disgraceful journalism.
In all honesty, if the Mirror are that hateful towards Alton Towers and Merlin, they need to be sent to the park and actually look how good the operations are. If they think Alton Towers are bad they should see Six Flags... I'm highly doubtful any of the reporters have been to Alton Towers.