Yes, it only happens on roads and pavements and WHEN ON THE LEASH. Walking up a country lane off the leash presents no problem - but then she walks at her own pace, sometimes dawdling behind sniffing, sometimes trotting ahead.
This is only a recent problem. Bumble is very obedient, walks to heel and has never pulled on her lead (except when a cat is in sight!).
She has pulled back and stopped before we get out of the drive sometimes, but it is far worse after a walk (usually about 30-45 mins). This morning we had to walk the last 200 yards of our walk a couple of steps at a time - so something is wrong somewhere.
She does not jump up as much as she used (she was trained not to jump up anyway) and she has never done stairs.