I love goldies
Many of them throw themselves onto the pavement and refuse to move - I see it more in goldies than any other breeds.
You need to reward the movement not lure her when she is already lying down.
To prevent the lying down energise the walk for a bit. Walk slowly, skip a few steps, talk in a high voice, reward her for looking at you as she walks, let her sniff, turn around quickly and run in the opposite direction calling her in a high pitched voice =- all of this onlead.
I know you didnt like what I said about her being bored but I do think you need to look at her focus on you and what she find rewarding.
If you were to write her bucket list from her point of view it would possibly include:-
Eating
playing - tugging
chasing
sniffing
cuddling - she is goldie
laughter
lying in muddy puddles
you know her better so there will be other bits.
Think of your interaction with her does it include this when you are out and about?
Probably you Let her off lead and let her go and do her own thing,
Maybe call her back for a treat but that lasts a few seconds but her sniffing which she is enjoying lasts so much longer. Again I am guessing.
Instead make your interaction with her more from her bucket list
Get her involved in a tuggy play at home to start with.
Dont call her but treat her every time she looks at you or focuses on you. Hide toys on the walk - drop them as you walk out and get her to find them on your return.
Have you heard of the rucsac walk - that is great to get dogs interest back onto the owner.
I just search on mumsnet and see you were given very similar advice on a thread earlier in the year. did you follow up on any of the advice reading Overfedstanley she is saying exactly the same as here!