I sent our local MP an email as well and they contacted HMPO on our behalf but said it’s a long wait to get a response back because they are so busy but it’s still a good idea to get in touch with them.
Also keep calling HMPO and ask to be put through to the ‘Customer Management Team’ as they have more access to application details and the first line of customer service representatives can’t do much for this issue.
8 weeks is a ridiculously long time to hold onto documents!