I think much of this is down to the behaviour of the website. We are in the same gold/silver row 1 boat. The website shows both front row seats available (as I could choose either) but it is not clever enough to stop me putting her in 1K, but then throws up the error message when I click confirm - although annoyingly, as usual, it doesn't say what the error is. If I do a dummy booking logged out, or on a different browser, 1K is shown as unavailable, as I would expect. You could try a dummy booking and see which seats are available.