Wanted to do Let Property Campaign but registered for Self-Assesment

Hello, I am trying to make a voluntary disclosure with the Let Property Campaign (LPC) and did my registration for self assessment yesterday. However I mistakenly registered for self-assessment and including the dates I wanted to disclose through LPC on the form. I'm being told this means I can't disclose through the LPC now and I will have to do full self-assessment which means I will face harsher penalties. I had already given the notification of disclosure to HMRC and expecting a letter soon. What are my options?

Hi,
You will need to contact the Let Property Campaign (LPC) team for advice:
Let Property Campaign
If you have already disclosed your income to the LPC team and the registration was carried out on a later date, your case may already be in the process of being worked. We would suggest that you contact our Self Assessment team 72 hours after registering to have your account closed.
Self Assessment: general enquiries
Thank you.