Currently managing LFC.
I changed some information in FMRTE for Anfield to have 65,000 seats. 100,000 Attendance in all 3 parts in the same section. Also 100,000 Season ticket holders.
I also then added BUILD NEW STADIUM in the Club Vision section for Supporters & Board, to both have a 10 rating. The Dates were also changed from START Date a few years ago and END Date 1/1/1900.
It is very important that when the new board offer new season visions, just accept them. Then wait 1 day in-game, then change the club vision again, Don't forget to save the edits. You can only ask for a new stadium to be built every 4-6 months. Depending on your clubs performances on and off the field, results and money wise.
I was about to ask the board to built a new stadium, when I see in the Inbox, they have plans to build a new stadium of 111,000 seats. Up from 65,000 seats. I think this is because of crowd average and Season ticket holders are 100,000 both of them.
Keep trying, eventually you will get a new stadium. Even if you have to edit the financial section on FMRTE for your club also. It has taken me 2 seasons and I have asked the board twice per season (Seasons 2 & 3).