Whilst it’s a tremendous backhand compliment revealing a level of subconscious inferiority - I’m not sure a few British retired pilots are going to revolutionise the Chinese Air Force.
Let’s remember we don’t have a “Top Gun” equivalent or Aggressor squadron and the last time a Brit pilot shot down an enemy aircraft was 1982, those pilots having long retired.
You can buy good books on tactics*, but at the end of the day it’s embedded QWI totally familiar with their aircraft’s performance and weapons - which I doubt they’d release to a foreign instructor - followed by hours of continuous training in ACT, 2v2, 4v4 and combat training against dissimilar types.
You can buy talk about battle management, flanking, beaming etc etc. But it has to become second nature.
Which is why we have, or had, so many exercises such as Cope Thunder, Red Flag, Mallet Blow etc.
Unless they’ve run off with th3 technical manuals for the weapons or electronics of something the Chinese want to copy or defeat I can’t see this as more than an embarrassment,, not a disaster.
* Recommended, if slightly outdated.