Plenty of information (including frequencies) regarding DACS / DAAIS is printed on the CAA half-mill chart.
Indeed. I recently did a VFR flight to Cherbourg via the KATHY intersection which is just south of the Isle of Wight. I recalled there is a VFR preferred crossing across the water route displayed on the half million chart, and there is an information box which mentions these Danger Areas and advises to contact Plymouth Military, also listing their frequency.
PiperArcher