For many years in the UK I had insurance that covered me for worldwide travel and work. Can’t remember who with, but many companies will cover for this. I’m now covered by our own company insurance.
For any new policy just make sure that you tell them you work with ROV’s and give them an overview of your job. Ensure they fully understand that you do not actually go underwater in a submarine and that for the most part (but not limited to) you work on a ships deck.
For occupation (should an entry be required) you should enter Remote Operated Vehicle Technician in full (Not just… ROV) so that there is no misunderstanding on perceived risk/payout should the need arise.
best regards
James Mc