As Spekesoftly has correctly said - the Hawarden Airport perimeter encompasses the whole of the Broughton factory.
For the record I speak with local knowledge - lived for 30 years in Broughton village, and worked 9 years at BAe.
Terminology must have changed since I left there too - the wingbox was the main portion of the wing and that was all made at Hawarden/Broughton (take your pick). Filton manufactured part of the wing equipping for the A300/A310/A320 - ie flap tracks etc.
I know the workshare has changed a bit over the last few years but the boxes are still made at BAe Chester.
cheers
JD