Double Probate and form Cap a5 c

I am a non-proving executor wishing to apply for double probate. The original solicitor refuses to discuss this with me or represent my application because of “conflict of interests” and no longer regarding me as their client. I am at a total loss to understand this situation and am not aware of any conflict of interest. They say that the situation is akin to representing both sides in a divorce!!

I am trying to obtain a copy of form Cap a5c but it is certainly not easy. Does anyone have a copy that might be emailed to me? It would be appreciated and would enable me to at least assess whether I might do this myself.