Grumpyjane - I do hope you get your own issues resolved when you speak to another GP but please, please, ask your practice manager to raise an 'Incident Form' ( they may have another name for it) this will mean that it will be properly investigated and you can ask them to let you know the outcome too.
It sounds as though she is confused between the different strengths of oestrogen creams and gels.
The advice you received wasn't just poor it was downright dangerous (her advice would lead to an increased risk of endometrial cancer) and this GP may well have seen many other ladies in the past ..... Or in the future....
Let us know how you get on ?
Pollie