@Jan Olieslagers - I found that calling them on the phone prior to submitting the flight plan helped a great deal. I was only refused once, due to military activity (which I understand is quite common).
Remember however that 8.33Khz spacing is extensively used in Holland, if you don't have 8.33khz compatible radio, you may need to ensure that your routing does not require any usage of these frequencies.
Good luck Jonathan, and have an incredible flight - I'd recommend going to Kinderdijk (South East of Rotterdam's airspace) and do a low pass to checkout these stunning windmills.
ps: Lille is fine without transponder, but they may complain a little... They will accept you for a Basic Service.
Last edited by alex90; 30th Apr 2017 at 23:05.
Reason: added ps