That's easy, ask SISU!
Reality is the club is worth nothing, but SISU want their imaginary £30 million back, so you would have to negotiate that based on how much they would save by getting rid now. Guess £15 million to get rid of them.
Charity half of the stadium probably £5-10 million, but you would have to prove future investment plus a plan for regeneration of the surrounding area to get the council to agree. Think 5 year plan of £20 million to cover current losses plus the costs of regeneration, but you could franchise out those rights to net off the cost.
Council half of the stadium not for sale.
Then investment in the playing side would need at least another £15 million.
So wildest guess would be £60 million plus.
The other option would be wait for ACL to issue a winding up order against SISU and take the club on after liquidation (would mean starting in non-league as we are not Portsmouth) which would save £15 million.
All guess work as nobody knows the real state of our club other than SISU who don't give a shit about it.
PUSB