The result is that Joe's property would end up as Bona Vacantia and then pass either to the Crown (which is represented by HM Treasury) or, for property in certain parts of the country, to the Duchy of Lancaster or the Duchy of Cornwall.
The Duchy of Lancaster had, at the end of March 2023, £641.2m of net assets under its control - (Duchy lands and property). King Charles III is Duke of Lancaster. The Duchy of Cornwall is a similar arrangement with The Prince of Wales as Duke of Cornwall. The Duchy explains how it deals with Bona vacantia.
The moral of the story is clear enough. Make a will and then keep it up-to-date. By doing this, Joe could ensure that his property went to the charities and not to the Crown.
ALWAYS get your will drawn up by a professional such as a solicitor who practises in this work. Most "high street" firms of solicitors do and they will be aware of the important legal requirements applicable to wills.
"Companies" can also be the subject of bona vacantia - e.g. Potier v Solicitor for the Affairs of Her Majesty's Treasury Crown Nominee for Bona Vacantia  EWHC 1524 (Ch) (14 June 2021) (bailii.org)