We had a talk on the subject at the local BFA meet, and had some first hand reports on the subject, as well as a talk from someone who has studied their behavior in France.
If I recall (?) the somerset hornet was already dead when found, and was believed to have travelled home in luggage from france.
The genes were weak and related to the french hornets in both the somerset and gloucestershire hornets..
A number of my hives are sat around the tetbury area, and will be making a few Hornet traps and setting them up at the weekend. The bait at this time of year will be Apple Juice.
The opening is important, and on several commercial traps, hornets may be reluctant to enter due to the width of the opening. However, widening the opening may also catch european hornets. Unless in the target area, recommendations on the beebase website should be stuck to.
It was also suggested, this year will be the last year DEFRA will fund search and destroy. 'if' they are here, and are still here next year, their attitude is likely to change.