Inherited 6 figure stock

Hoping this is the correct sub?

A family member died in 1988, in their will was an impressive estate where plenty of people would benefit and have an 'easier' life.

The portion of estate was set aside for when those too young to obtain at time of death was to be held until their 21st birthday, the portion side up for is youngsters was put into stocks. We each received our stocks excluding 1 at different times. The biggestvwas due to be kept until the youngest reached 21 then would be sold.

Now all of us born prior to 1988 are older, the solicitor dealing with this was bought out and a new company took over the dealing. Everyone's details was lost during the transfer.

Fast forward many years later in Dec 21. We are finally found.

The stocks and interest was counted up and the solicitors did their checks etc. We all wanted to sell our stocks(shares).

The solicitor has put this forward to the registrar of the company dealing with the stocks. Between myself and other parties due to inherit we are getting conflict timescales.

For a TLDR, here's the question I'm here to ask.

How long til the request to sell a stock does it take to get the money?

Thanks to anyone helpful enough to shed some light.

England, UK.