Do I Need an FCS (Passenger Locator Form) if Entering Spain by Road?

Thanks for helping out. I'm entering Spain via a flight to France and then coach transfer to Santander in Cantabria. I have all in order to arrive in France but would like to understand:

• If I need an FCS (Formulario de Control Sanitario / Passenger Locator Form) to enter Spain by road
• If so, how to obtain this for entering via road, the website only has options for arriving by Air or Sea

Note that everyone in my group is originating from the UK, is fully vaccinated and has the NHS QR code that is accepted in Spain to demonstrate this when required.

So far I've looked at the relevant French travel guidance which makes no mention of the FCS, Looked at the Spanish guidance which says the form is necessary but then links back to the air / sea page linked above and tried generally googling for an answer but arriving by road appears to be a grey area.

I'm keen to avoid problems on arrival and one option would be to fill out the FCS with details of the flight into France but I'm unsure if this would be accepted by the online form. Does anybody have recent experience of how to fill in an FCS in Spain if arriving by road or know if this is required?

Thanks,

James