Ferry to UK from Dublin Port

Weight is not an issue on the ferries, all they care about is height and length. Your biggest concern should be if your car will be able to manage if the crew direct you up a steep ramp to one of the upper decks but the ramps have good gripping surfaces so you'll probably be ok.

Should be no problem

Never an eyebrow raised over the most jam-packed of cars, once when I hired a Transit van they just asked if I was private or commercial, but even then they didn't look inside.

Back in the 80s the customs at Holyhead/Liverpool would sometimes ask you a few questions if you looked like a suspicious Irishman, but these were just related to checking your identity and making sure you were not a "known" person, and they never bothered about belongings either.

I must have looked pretty suspicious in my 20s, as I got stopped all the time.

And it wasn't just customs:

One day my (then) wife was in a bank and I was waiting outside for her, and she heard the manager tell another staff member to keep a close eye on the suspicious looking guy hanging around outside.

On another occasion, my wife was having a job interview in a Surrey town. I found some parking beside a row of shops close to the office where she was being interviewed, and sat in the car reading a book. After 45 minutes the police arrived, one of the local shopkeepers thought I must be up to no good.

So, OP, you're fine . . as long as you don't travel with me!

C635