A couple of other pointers to watch out for.
Danger area 119 is often active up to 5000ft and of course you need to be above 2000ft going over the Nuclear power station at Hinkley point.
The base of the airway N864 raises at EXMOR to FL65.
We descend and climb aircraft outside the Airways into and out of Cardiff, Bristol and Exeter there so I would recommend you are speaking to one of the LARs units in that area.
It may make it sound very complex but it isn't really and as long as you are in contact with Cardiff, Bristol or Yeovilton LARS they will be able to tell you the status of D119.