FWIW, I have 60 years of sailing experience, but wife wants to sail to
Croatia.
Croatia requires all captains in their territorial waters to have an
ICC or equivalent.
I looked at the different possibilities and the RYA wanted a 5 day practical exam as well as their online theory course.
I found NauticEd in the US, took their online course, also the
Florida Boating Safety course and a 6 HOUR practical exam in Tampa Bay. I got a BBCM/SLC
license from NauticEd and the Croats specifically accept that.
I paid less than $1000 for the whole program including
renting a sailboat in Tampa Bay.
It is important that if you plan to sail with your wife that she feels confident in your boat operating and that she could "take over" if something happened to you.