Thank you for all your kind replies!
The controller who lectured me was neither arrogant nor grandstanding, just - stern. He made me feel like a fool, which I was, so that's only fair
As for your fine suggestions, VAT-Spy is Windows-only, and I'm running Linux. Accomeap and VATtastic look nice! I'll definitely check with those next time!
And - sorry I have to ask this: If I want to take off from an unmanned airport within a controlled area, I contact that area controller for IFR clearance, taxi, push&start and departure, right?