How can Dev-Tec start-up in the United Kingdom

Final Research Project: Foreign Entry Strategy (Group Project): Dev Tec Ronin Helmets from Japan
my part What is the overall process of becoming a company in the select country? What are the Policies and Procedures for this?The process in the legal start to finish to be a defense company as a legal entity in the United Kingdom.What’s the procedure and patents required to get the Dev-Tec Ronin Helmet on the market?Political Policy and Regulations on defense companies, is there anything that will block out Company? Can we fix it and be successful?