When does 90 day timeperiod starts

[imrankpt]

Hi, my appeal was allowed on 11th October by FtT. HO seek permission to appeal to Upper Tribunal on 23rd October 2018. FtT refused HO's permission to appeal to UtT on 20th November. Home Office did not seek permission to Upper Tribunal directly. I understand that HO has 90 days to implement FtT determination and process the application however my question is that when does 90 days time period starts?

1: From the date when appeal was initially allowed. i.e. 11th October ; or
2: From the date when FtT refused HO's Permission to appeal to UtT. i.e. 20th November