Level3 CDN issue affecting RTMP HD downloads

[SquarePenguin]

Currently there seems to be an issue with the Level3 CDN that supplies
RTMP HD downloads of iPlayer content.

This issue was identified by 'tvfan' over in the forums[1].

A resolution workaround has been identified by dinkypumpkin[2].

Hopefully this issue won't last too long and things will be back to
normal shortly. 

[1] https://squarepenguin.co.uk/forums/thread-520-post-2792.html#pid2792

[2] https://squarepenguin.co.uk/forums/thread-520-post-2796.html#pid2796