I’m another IRATA L3 but feet firmly on the beach.
IRATA L1 ticket, then GWO tickets then some more stuff depending on the actual job you intend to do.
Where are you based? Belay is the name of a very good training venue down Shoreham way who do IRATA and GWO training.
I would caution that it is potentially expensive to get ‘ticketed up’ and all have expiry/reval requirements so it can be a bit of a gamble. The training providers will happily sell you all the courses you will pay for with little care over whether they are useful to you, IME.
Personally I would look at doing the IRATA L1 then looking for some onshore work, which as a newly qualified tech would most likely be window cleaning, geotechnical (drilling/netting/de-veg work) or the joys of riser/silo cleaning but apart from the jobs themselves you’d be gaining valuable rope hours and also deciding if a career spent handling off stuff is for you!
I stayed on shore as I like to be home in my own bed too much.