Defford is without doubt closer and about the same amount of fixed wing as Bidford. Gloucester is the quickest to get to for rental, Shobdon about 1hr 15min, HG about 1hr, and Gloucester about 45 min.
If it was your own aircraft then lots of Flying Farmer Strips within 15 minutes of Worcester.
Defford and Bidford are grass and do get muddy in winter.