You might find it difficult if not
impossible.
23 years ago I bought a new 125cc. I got full comp only because it
was a new bike and the cost for cover was £400 with high excess, with a full no claims bonus (in 1988). I had just come from UK where
full comp on any bike up to 350cc was £70.
My 600 Yamaha is insured with Linea Directa,
but only 3rd party and breakdown and that is about 250 Euros, 100 euros less
than with Liberty Ins which I changed from two years ago.
Good luck Alfonso
PS I tried to get a Linea Directa Tel No. but all I could find was this, which appears to be an agent for them (in English) 800 200 369, if they do not do full comp maybe they could recommend someone