I have a 1948 cessna 140 registered N and based in Italy,insured with Axel Neuman in germany.
The only restriction is related to who's piloting the plane,which in this case is only me,no big deal.
for the rest no restrictions,it's valid all over europe (no need for a world wide coverage),I pay aroun 550 euros a year for third party only,and it would cost about 1.100 euros for full coverage (hull loss,fire,theft and so forth).
They only asked me how many hours I had before giving me a quote.
Pretty simple.