Private ltd is tax free it won't effect your reported income at all, I don't see how it could effect anything your employer does. I had private ins on my mortgage and car loans, basically the same situation you are in. Just don't ever discuss it with anyone, it's not their business, why bring it up. It's not income! IMHO, you are extremely lucky and in very good shape since you did buy this private insurance 30 years ago, congratulations!
BUT, you need to get with a lawyer for a real answer. I would suggest a disability specialist.