Fuji
To answer your question about the clearances - you can't - pure and simple.
Once you leave UK airspace you are a bare bones PPL. IFR flight requires an IR - you haven't got one, you can't do it.
The old "IWR" proposal is dead and buried. As far as JAA is concerned they have harmonised licences. The IMC being a NATIONAL rating only it does not exist in the JAA's thinking.
CM