Having read up a bit on cleaning resin prints I concluded that the problem was uncured resin left inside the hull by inadequate cleaning - a likely possibility given that the underside of the hull is quite closed off. Unlike the first model, this didn't seem to have cured at all or damaged the underlying detail - maybe there had been insufficient time exposed to UV before it was packed and shipped?

Bearing in mind the warnings from Roger Dawson's post and from other reading / YouTube videos, I got my PPE out and cut the hull and island from the frames and gave them and the details on the island frame a good wash in Isopropyl alcohol and then hot soapy water. After the first pass, most of the liquid resin was gone - there wasn't much in volume terms to start with. I've given it a second wash today - but there was still resin seeping out so I cut the base of the hull open and really flushed it out - that seems to have done the trick. Next it can sit on a nice bright window ledge for a few weeks!

It is clearly unacceptable to send a model out in this condition and it is extremely frustrating as the underlying model has so much detail and seems to be well proportioned - I've not checked it against plans yet.

I think t producer would have a really great product if they could just make a few simple changes:
- Modify the hull design so it doesn't trap uncured resin and can be washed more easily.
- Pay more attention to to the washing stage.
- Fix the weird paving slab effect on the flight deck.
- Simplify or slightly beef up some of the thinner features.