Just, again, took the overnight ferry to UK, with car. Very relaxing, comfortable, good value. Depending on arrival port you arrive 07.30 or 09.00, refreshed, watered & fed with your own car and all you chattels. The alternative would be an 07.00 flight = getting out of bed at 04.00 then renting a car. You lose an evening at home, but the cost is not so much more than a flight +++. If you planned an evening hotel at one end then the ferry really wins; if you operate not too far from either port.
The same is true for the X-channel ferries. Book a late one turn up for the earlier one; no bother, no charge, no fuss and with 20min checkin possible if you can get through the passport check. Driving from Dover to London in your own motor, or trying to survive any of the airports and train. No brainer.