I was using the term "airways" as this is the term in the ANO.
The fact is if you plot EGWC DCT EGCJ using SkyDemonLight at 5,000', SkyDemonLight shows infringement of the south eastern corner of Class A M605 [which is 4,500' at the infringing location]. I believe that the location of 'airway' M605 by SkyDemonLight does correctly correspond with that in the ANO of 7-Apr-2011, which says (as far as I can tell) that M605 Class A is 10nm wide. I am happy to be corrected, but I suggest you try plotting it yourself. And M605 is only one of several examples.
However, if you plot exactly the same route on the current edition 37 CAA chart there is no infringement of M605 (and the infringing part of M605 is not shown on the CAA chart). Hence my confusion.
On a practical level I agree with you - I intend to take the CAA charts as the definitive guide of CAS.
Which is disappointing for SkyDemonLight - in my opinion it needs amending to match the CAA chart (+amendments) to get rid of these anomalies.