The EASA NPA won't be released until June 2011. Then there will be a consultation response period before the final draft goes to 'commitology' and finally to the European Parliament.
Which means that it will be impossible for any associated rule change to be in place by Apr 2012. A point which has beeen put very firmly to EASA!
The CAA's understanding of the role of 'opt out periods' and the ability of the FCL.002 group (which hasn't even been formed yet) to sort things out has had to be reviewed. So quite what the UK's strategy will be remains to be seen!
'Grandfathering' will be insufficient. The UK isn't prepared to accept the loss of flight safety for the administrative convenience of €urocrats.