I teach this course at AFTRS (Australian Film Radio and Television School) based at Fox Studios in Sydney if you are ever over here. No teaching of dive skills purely underwater video and cinematography
Even if Dragon is released at NAB I'm sure it will take another 12months to actually get the upgrade. 2nd is that they have said that Scarlet cannot be upgraded but there will be a trade in scheme. However when looking at a camera that will likely cost around $28K minus trade in say $7k still $21K to find. Not pocket change.
I haven't watched all of it but the lines are probably due to the interlacing, options to solve this could be, download JS deinterlacer (free) and run it through that, I presume you shot 50i coming from the UK so export as 25p and try upper field first. anther option is to setup a 25p timeline and drop the footage into that and render and export as 25p.