Revised decision after MR

Hi,
I received letter today re a revised decision to treat me as having Ltd capability for work. Thank you for all the help I received from the member guides, which helped me to calm down and keep going.
My Question: I started receiving ESA in August 2018. After my assessment in Jan 2019, this was stopped on 14 Feb 2019. In my letter, it states "You are placed in the WRAG to be re-referred in 18 months". When does the 18 months start (Aug 2018, Feb 2010, or from date of letter).
I'd be grateful for any insight.
Many thanks
Amix

Thank you Gordon.

I'm still taking the news in - I didn't believe I would be successful. This is after a local Rethink support worker told me they didn't think I had enough evidence and were not prepared to help me once I'd been rejected after initial WCA and scored zero points. That led me to your site, and made something overwhelming less so, and gave me some sense that even without help I could attempt a MR. I AM DEEPLY GRATEFUL to Benefits & Work for having something so complicated made accessible, even during a time of paralytic stress. I also received unbelievable support from Money Matters Charity, who believed in me, told me I had a case without question, and encouraged me when I wanted to give up. At the same time as doing the MR, I was also having to complete a UC50, to go through essentially the exact same process as for the ESA50. Luckily, I got the result of the MR before the WCA date came through. Thank you very much.
Amis