Most insurers will cover you fine if you say you plan to fly less than 50 (occassionally 100) hours a year.
That has to be provably the case when you start the cover; afterwards you can fly as much as you like.
Some brokers advertise in the back of the aviation mags, claiming special deals for pilots. In reality these tend to be just the standard 50/100hr deals, but they are worth a look. I recall Legal & General features prominently among them.
Much over 100hrs will be a bit of a problem; you end up paying more.
So if you haven't started flying yet, now's the time to do this - you don't have a problem because you aren't flying at all!