Ebbsfleet International car parking promo codes?
 

Bit of a long shot, as a quick web search suggests they don't exist (and possibly never have done), but has anyone come across promotional codes for discounting pre-booked parking at Ebbsfleet International railway station in Kent (which is served by Eurostar and domestic Southeastern Highspeed trains).

I only ask because there's a "promotional code" box on the parking pre-booking page, not that that necessarily means much.