Anybody that has a vacuum chamber and the skill can resilver a prism, the transmission ratio is critical, its not 50%. I have found a couple of places in the U.K. that can offer this service, I had one aluminised and it was good enough to not be noticed by an expert dealer. This subject is periodically raised and Peter at CCR is the expert but Malcolm Taylor can also resilver and repair a split prism. Timescales may vary.
Best,
normclarke.