I just saw a post, elsewhere, about an event that may impact if you're sailing from Liverpool on 3rd June, this year.
Apparently Cunard are naming a new cruise ship, Queen Anne, on the waterfront.
Now I know that it won't be happening at the Steam Packet terminal, but traffic will be very heavy in and around Liverpool on that day.
Quote-
The event in Liverpool is expected to draw tens of thousands of spectators to vantage points alongside the river at Pier Head

Maybe allow a little more travel time?, just a thought.
It may make no difference whatsoever!