A difficult rifle to put a value on. Quite niche and they don't come up for sale too often. Probably a small but keen pool of buyers for them.
I paid £200 for mine last year in a private sale, which I consider a bargain. It's in similar condition to yours I'd say. Knowing what I know about them now, I would have no problem paying a fair bit more than that for one. They are superb and I'd never part with mine.