You are absolutely correct in stating Plymouth Military give away airspace when it is not required. Every morning Exeter, Western Radar and Bournemouth are contacted and given approval to transit through danger areas 012 and 031 without having to contact Plymouth. GS Channel and sector 6/36 are contacted and given off route status through the danger areas for CAT for durations when there is no hazardous activity to affect them.
To clarify some comments previously made by other members:
Although the danger areas have published times, it does not mean there is hazardous activity taking place for the whole period. The activity starts and stops throughout the day and has different altitudes. Some activity may be planned, for example, to take place for 2 hours but finishes after 90 mins. That's where Plymouth Mil, Swanwick Mil and London Info can provide up to date information and a crossing clearance when possible, maybe with an altitude restriction.
I know some pilots who have infringed the Danger Areas have stated they "checked their notams, but didn't see anything to say they were active". There would not be a Notam if the activity was occurring within the times and heights that the danger area was published as active. The AIP says it's active.
There used to be a recommended VFR route through D036 from SAM to MP (Cherbourg). Although recommended, it was also conditional on what activity was occurring within D036 whether pilots fly could that route or not. This point was stated in the guidance issued as an AIC, which I sometimes used to think was missed or skipped!
A: I'd liked to transit D036
B: Unfortunately it's active with live firing, you'll need to remain clear, route via ORTAC.
A: Can i fly the recommended VFR from SAM to the MP?
B: The one that penetrates D036?
B: Err no, it's active with live firing!
An ATIS type system would be unworkable. Plymouth and Swanwick Mil provide a DACS for D003, 004, 006, 006A, 007, 007A, 007B, 008, 008A, 008B, 009, 009A, 012, 013, 014, 017, 023, 026, 031, 036, 037, 038, 039 and 040 (and breath
). All with different activity at different heights at different times, that could change at short notice.