It’s a bit too late for him now however I take a different view to the others.
In similar situations when my 24/45 is already completed and if I can get onto the ferry using two interruptions totaling less that one hour then I set the tacho accorgingly and my Day/Week doesn’t start until I drive off on the other side.
From disembarking the ferry I now have 6 x 24 hours (144) maximum before I must commence my next weekly rest.
No control has had a problem so far.