Oh dear. Things aren't starting well. Comparing the bulwarks of the boat with it's hull, there's quite a difference. The top and bottom you see in the photo should match, and the top part is quite a bit short.
At this point all I can think of is the Brede Lifeboat kit I bought a few years ago and ended up throwing in the bin as the parts were beyond saving. I appreciate that kit development isn't free, but you would think that the bits could be better than this. Fortunately, the makers of this one have long since retired, so I can say what I like...
Matters don't improve when I cut out the deck using the plan either. It's quite a bit bigger than the hull! Not consistently either, so this isn't some weird photocopying error.
In the end, I cut the access holes in the deck and stick the hull to it with lashings of Precision ABS glue. A least a deck too large can be rimmed back.
I'm going to build this thing no matter how it fights me!