Having read this thread and remembering an article in a UK magazine about this a while back, would it be safe to say the following:
- On a Night VFR flight from mainland Europe to the UK, the flight is logged as VFR (because Night VFR is just that, in mainland Europe) and so no charges would be raised by Eurocontrol
- On a Night VFR flight from the UK to mainland Europe, the flight is logged as IFR (because all flying at night in the UK is automatically under IFR) and so charges WILL be raised by Eurocontrol
If I remember correctly, if the flight is explicitly logged as VFR first, IFR later or the other way around (an Y or Z flightplan), you'll only get charged for the IFR parts. But if you do an implicit transition from IFR (UK) to VFR or the other way around, on what is commonly known as a Night VFR trip, the whole flight gets logged under it's initial status, which is VFR in mainland Europe, and IFR in the UK. Correct?
So - fly out of the UK in daylight, return at night... ! But if you do fly from the UK to mainland Europe, make sure you submit a Y flightplan, changing from IFR to VFR at the FIR boundary.
Maybe somebody in the ATC forum would be able to confirm this?