Man UK! That sucks and blows at the same time. They can do alot with Al now days but I voted to scrap it for the money you have invested and try and recoup some of the greenbacks.
But depending on where most stress is centered on that particular bike frame may persuade me to keep it. I have no idea and speculation alone would not be enough for me. I would contact the frame builder to see. Is it a new frame you bought or a used one? If new I am sure you would send back for replacement so I take it that it is used**********