The Government publishes Official Statistics (on a quarterly and annual basis) of licences granted and refused for military exports on GOV.UK, which can be found at: https://www.gov.uk/government/collections/strategic-export-controls-licensing-data
The total value of military rated items, licensed between 1 April 2017 and 31st March 2018, was £894,505,658.
The value of exports licensed in a given period is not necessarily a measure of actual exports shipped in that period. This is because most licences are valid for multiple shipments over two years and export values are only available for a subsection of licences (Standard Individual Export Licences). Some licences expire before they are fully used and in these circumstances exporters must apply for a new (duplicate) licence, which can result in a significant element of double counting in some periods.