we don't have Minimum Vectoring Altitudes. We are allowed to use radar vectors which keeps you 3NM from or 1000Žabove obstacles and of course inside controlled airspace.
That sounds a lot like an MVA!?
People often mistakenly assume that you cannot vector below the published MSA, but the two things have nothing to do with each other at least not in our case
I don't think anybody was refering to the MSA. As you say, that is a completely different thing.
We have an MSA of 4300' but several MVA areas that step down to 1500' which, as you point out, is possible over the sea (accounting for a few tiny rocks/islands).
Once the aircraft is on the approach below 1500', there is nothing we can give in IMC except a missed approach.