Um cidadão indiano (com 2 anos de visto válido no Reino Unido) pode visitar Montenegro sem visto?

Sim, você pode entrar no Montenegro com visto válido de 2 anos no Reino Unido por até 30 dias sem visto. A resposta é do site oficial do Ministério de Relações Exteriores de Montenegro :

link

--- Overview of visa regimes for foreign citizens ---

Holders of travel documents containing a valid Schengen visa, a valid visa of the United States of America, United Kingdom and Northern Ireland and the Republic of Ireland, or a permission to stay in these countries, may enter and stay, or pass through the territory of Montenegro up to 30 days, and not longer than the expiry of visa, if the period of validity of the visa is less than 30 days.

Holders of travel documents issued by the European Union Member States or the United States of America, Kingdom of Norway, Republic of Ireland, Swiss Confederation, Canada, Commonwealth of Australia, New Zealand and Japan based on the Convention Relating to the Status of Refugees (1951) or Convention Relating to the Status of Stateless Persons (1954), as well as Travel Documents for Foreigners may enter, pass through the territory of and stay in Montenegro up to 30 days without a visa.

Mere possession of a visa does not grant the entry to Montenegro. Other legal requirements for granting a foreigner the entry and stay to Montenegro must also be met according to the Law on Foreigners (“Official Gazette of Montenegro”, no. 56/14 , 28/15 and 16/16.

Visa regime between Montenegro and other countries is regulated by the Decree on visa regime (“Official Gazette of Montenegro”, No. 35/16).

Visa in itself does not offer a grant of permission to work in Montenegro. Person who intends to work in Montenegro must obtain a temporary residence permit for the purpose of employment or seasonal work, on the grounds of previously issued work permit.

Além disso, o titular de um passaporte indiano comum precisa de um visto de Montenegro:

De acordo com TIMATIC , isso é correto, você não precisa de visto para visitar Montenegro quando estiver:

Passengers with a visa, valid for the period of stay, issued by Ireland (Rep.), USA, United Kingdom or a Schengen Member State for a maximum stay of 30 days.

O IATA Timatic é o que as companhias aéreas e agentes de viagens usam para verificar os requisitos de documentos de viagem de passageiros para pontos de destino e de trânsito.