I’ve just done a (roughish) count of Onward’s cabins & I make it 26 inside cabins in total and 79 Oceanview in total. On top of that there are 160 veranda, 10 veranda plus, 56 Club Continent Suites & 10 large suites. That makes 341 in total which is about right.
Don’t forget that some people may have booked a ‘guarantee’ Oceanview, so if you do a ‘mock’ booking to look at vacant cabins, their cabins will still show up as empty.