Personal Health Insurance: who should obtain medical evidence?

I live in England. My Personal Health Insurance has been turned down because no medical evidence was sent in by my employer who was handling the claim. My employer says this was not up to them but it was up to the insurance company to obtain it. Who should of obtained it. I myself provided evidence to my employers but they never sent it in with my claim.
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if your employer had it, they shouldve passed it on when asked to do so. it is not your responsability to dot his unless they ask you
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