Hi Daniel Harrison ,
I was in a similar situation on a number of occasions.
Scenario 1 - 7 app, 5 weblink Kiosk build. Catering dept. who wanted to take pictures of the meals produced for the their web site menu, so they needed access to the camera as a standalone app.
Solution 1 - Added a 3rd party camera app, I think it was called 'Open Camera'.
Scenario 2 - Single app Kiosk build. The app required access to the camera, but had a basic UI within the app.
Solution 2 - Created an App configuration policy for the app, granting access to the camera, local storage etc. One issue though, was that the users were not able to view the pictures taken; on the device. So were not available until they uploaded them. To circumvent this; I installed a 3rd party app called 'Simple Gallery'. This allowed them to view the pictures/videos taken. Shortly after the Vendor contacted the gallery app developer and added a simple gallery/media viewer to their app.
Hope this assists in some way. Whether in Kiosk or Fully Managed mode; separating, enabling/disabling the system apps is an all or nothing game at the moment.