what is transportation height of Fairline Squadron 55?

Many Fairlines are designed for use in the Med and thus have detachable flybridge windshields and radar arches for road transport. All depends on which model you are looking at.

Just phone Fairline for any info, I'm sure they will be joyous to take your call.

I don't know for sure, but it should be the bridge clearance plus the draft. Now, you can probably knock up to a foot off if the props are removed (if they're the lowest point) and probably remove some items from the flybridge of the vessel to get it down further.

But, a call to Fairline should tell you

Fairline list transport heights on their web site. A phone call to make sure cant hurt.