Comiserations on the change of ferry sailing days.
Sounds like it will add an unwanted cost to the holiday.
For what its worth,
When we went the organiser took one transit van and we piled all our gear in there. Me and my buddy peronally booked twin cabin, which I recal being ~£200 each. I think we all paid ~£30 quid each (we booked the whole dive boat) to the organiser for our share of the extra ferry costs for the van and car parking charges in Bergen. Most booked their cars into the secure parking in Newcastle. Its a bit of a hike in Bergen from the ferry terminal to the boat mooring so I'm glad we had the the van to move the bulk of the kit, Just hand luggage to shift on foot.
We were lucky that at the time their were sailings which dropped us off and picked us up the same day of the week in Bergen.
If you have only booked places on the boat the skipper might be able to put you in touch with others who are sailing on the same days, and you may be able to arrange to share car/van space on taking the kit over the sailing?
Good luck. Bergen is a lovely place and the diving is really nice. I don't think I'll be able to afford to go to Norway for a few years, now my family has expanded.
Dave C