Looking for some help wrapping my head around returns and carry if a business is not sold at the end of year 5.

In classic Search Fund models, an exit is assumed at Year 5, and LP IRR/MOIC is calculated at that time with market Enterprise Value. The Searcher/GP carry is paid through the final tranche according to the LP investors' return.

Question I have: What if the business isn't sold? How is IRR/MOIC calculated? How do you determine market Enterprise value of the business?

Further details: I am wanting to hold a business longer term (10yrs+). Some of the LP investors are also looking for a longer hold. How would I calculate my carry at the end of Year 5? 3rd Party valuation? Using the entry multiple on the new EBITDA?

Appreciate viewpoints here...