It sounds as if you probably suffer from Reynauds to a greater or lesser degree. My bettter half suffers quite severely from this and she has to work reasonably hard on the bike for several miles before it becomes tolerable. Most good quality windproof gloves are similar in their effectiveness, in other words your hands are still feeling cold even with the very best gloves. Try wearing a balaclava, this helps to prevent your skin sensors triggering and sending messages to your body thermostat to shut down blood supply to extremities. In other words try to have as little exposed skin as possible, on top of this work as hard as you can on the bike.
