No, you haven't - descent from William the Conqueror doesn't take precedence over descent from Edward III. Your principal problem is that Edward III was the King. As such all property which he could have willed to his descendents was so passed on, or remained vested in the Crown. The latter goods, chattels, rights, privileges and family silver belong to whomsoever is currently rightwise King, or in the present case Queen, of England; so no luck there. Anything not passing to the Crown has already been divvied up and distributed to the relatives and one must presume that your ancestor(s) got their share in due course; and probably spent the lot.
Of slightly more interest was the fact that Edward III's succession was a tangled web. (See Richard II, Henrys IV, V and VI, Edwards IV and V and Richard III - in other words the Wars of the Roses. Who knows what skullduggery may have gone on to deny you your birthright?
If you are planning a return match, a sort of Bosworth II, to reclaim your inheritance, do let us all know - tickets could be sold, commemorative mugs could be produced and refreshment stands could be organised. In fact Silverstone is looking for a new attraction to replace F1 for a few years at least - jousting and trial by combat might go down really well!