The ToR states that the Lead Partner must be a public body or a body governed by public law as defined in Directive 2014/24/EU. Is a public limited company considered a public body? Is there any documentation the Programme would require to prove the LP status at application stage?

you can refer to the programme manual (p.24)
“Public equivalent bodies :
• are established for the specific purpose of meeting needs in the general interest, not having an industrial or commercial character;
• have a legal personality;
• are financed, for the most part, by the State, regional or local authorities, or by other bodies governed by public law;
• or are subject to management supervision by those authorities or bodies; or have an administrative, managerial or supervisory board, more than half of whose members are appointed by the State, regional or local authorities, or by other bodies governed by public law.”

If needed, any documentation will be asked by the national authority during the eligibility assessment process, therefore after the application stage. For this reason, to be sure beforehand, we invite you to verify the status of the entity with your national authority