St malo Brittany Ferries parking?

I’m (hopefully) on tomorrow’s/Thursday 2030ish St malo-Plymouth crossing but I’ve turned up 24hrs early, first time here and the brit Ferries website says lorries can park in the lanes outside overnight to check in the next day, but it seems tiny, and don’t want to have to get checked in at silly o’clock in the morning and not be able to wander into town.

Anyone know if there’s somewhere better, preferably free, to park until tomorrow afternoon?

As you turn into the port entrance by the swimming pool/leisure centre there’s 4 or 5 parking bays immediately on the right before you get to the security gate.
No problem parking there and wandering off to the town but obviously space is a bit limited.