Received from Iain,
Dutch Monoposto dates:
*12 – 14 April Voorjaarsraces – Circuit Zandvoort (to be confirmed)
https://www.circuitzandvoort.nl/
24 – 26 May Nürburgring Classic – Circuit Nürburgring (confirmed)
https://nuerburgringclassic.de/en/
*5 – 7 July of/or 20 – 21 July Circuit Zolder (to be confirmed)
https://www.circuit-zolder.be/
15 – 16 September Trophy of the Dunes – Circuit Zandvoort (confirmed)
https://www.circuitzandvoort.nl/
4 – 6 October SuperSpa – Circuit Spa-Francorchamps (confirmed)
https://superspa.be/