When the enhanced security requirements were first announced by the DTLR on Tuesday afternoon, EZY immediately tried to attain this standard.....100% handbaggage searches at the gate, etc. Given the resources this entailed, the turnrounds were absolutely hammered, and cancellations resulted.
Some other airlines took a more progressive view and aimed to attain this level gradually over the coming 24-36 hours, so were not carrying out the requirements 100% on Wednesday. (Random 20% searches at some airports) so were not as badly affected.
Between Wednesday and Friday, as 'the dust settled' and airports and airlines began to co-operate, and resources were found, the programme began to settle back down.
Had the airline taken a more progressive view regarding Wednesday's programme, the results may have been different.