Sierra Security Limited is rated 3 out of 5 in the category security and investigations. Read and write reviews about Sierra Security Limited. Sierra Security Ltd is authorised by the Ministry of Justice's (PSPLA) Private Security Personnel Licensing Authority to operate as a Security company - authorised to provide security services. The Director Simon de Boer, obtained the necessary prerequisites (COA & SC) to apply for the registration of Sierra Security. Sierra Security is based in Thames - providing security services to the communities of Coromandel, Thames and the Hauraki Plains.