Begins with a D, I think.
My last: 1d (Long unspecified period of time?). Is it Years, Yearn or other? Years seems too literal (no cryptic element?) and while to long is to yearn, I can't see the rest of any parsing.
Thanks for all other hints posted. I agree with Jazzgirl re. 5d - 'domestic channels' might have been a better clue.
Cheers - A-P