Advice please re DWP refusing to contact GP

Please can anyone advise if this is correct. Was claiming ESA and last ESA form filled in approx 2 years ago. Moved house 16 months ago, updated DWP. Invited for face to face in Oct took prescription medication with me showing GP and address which the assessor who details in report is Physiotherapist took from me made notes then handed back. Declined ESA for mental health deemed fit for work . Requested MR and specified GP details requested they be contacted. Within M.R. decision which was still refused they sent copy of form sent to my old GP practice which of course was returned patient no longer registered here. Appealed and again requested GP be contacted and gave details again. Appeal declined now have date for tribunal. Appeal paperwork and MR paperwork states for me to supply medical evidence. I have asked 3 GPs at the practice on 3 diff occasions even offering to purchase something they’ve all refused saying “onus is not on you it’s for DWP and they say protocol in place between DWP and GP” I just feel I have important information on my medical records to be considered for no-one is willing to ask or share it . With this in mind I feel the appeal hearing is going to go in DWP favour again, any advice I can bring up at hearing appreciated. Thanks

I thought GPs under their contract had to reply to requests from DWP for information on patients?

Thank you for your reply Gordon. I showed the GPs the response letters following MR and appeal where they said it’s for me to supply medical evidence. Unfortunately despite seeing 3 different GPs within the practice and offering to purchase letter they all refused alleging that some protocol is in place between DWP and GPs . I just feel the odds are stacked against me for appeal. It’s all disheartening that they wrote to wrong GP practice and won’t re write to correct one. Lisa