JAA flight planning?
 

OK, here is the scenario. You're planning a trip to an airfield which is below minima so you need your 2 alternates under JAA rules - both with weather at or above your planning mimina. In this case your alternates have to be one category better - i.e. if the airfield is Cat 2 equipped the wx. needs to be Cat 1 or better etc.

Right then, you blast off and while airborne you discover that your destination is still unavailable due weather and in order to be legally allowed to proceed you need at least one alternate that you can use.

Here is my question - when deciding if you can use an alternate in this case, do you use the normal aerodrome operating minima or do you have to reduce it by one category as you do when still one the ground?