BHD does have the ability to operate international routes - Flybe currently operate weekly ski charters to both Salzburg and Chambery with Q400s and 146s respectively. Astraeus will be operating a programme in July & August with charters to Malaga & Alicante using 733s.
This and the current service to ORK would probably explain the requirement for permanent customs facilities.
The initial Air Route Development funding has been exhausted and a further allocation has been requested.