What they do outside the 12 mile limit (work wise – UKCS included) is of of no legal concern to UK immigration.
I am wondering if the UK immigration cares for offshore work. For example when an offshore vessel, coming from let’s say the Norwegian Sea with mainly Filipino crew, has to work in UK waters for appr. 1 week and the work location is 10 NM from the shore than I don’t expect that they first have to sail to Aberdeen for a crew change.
This might change when they have to visit Aberdeen multiple times for bunkering.
In 2000 I was working in Canada and remember that most of the Filipino’s were replaced by locals but not the Filipino ROV pilots.
In 1999 I started training Filipino ROV pilots for my former employer on the North Sea. They were replacing the British pilots. The Filipino ROV pilots were a little cheaper but were also better educated. Most of them had done an electronics or electrical course on an university. Most of these guys are working for Fugro in Singapore now.
At the end I paid my price because I lost my job or actually I quit my job.
Recently I was asked to give ROV trainings in Manila, Middle East (Unique Group) etc. but decided to go my own way and haven’t seen an ROV in 2 years now.
The only thing I never liked about Filipinos were a the karaoke parties…