moorwalker, I would say if it ain't broke, don't fix it. If you are happy with Indivina then why risk changing it for something else? If you were starting HRT from scatch aged 60+, it would be a different matter but I don't think there is any increased risk if you have been taking it for years and as far as I am aware, it is only starting oral HRT post 60 that poses a risk.
A lot of women come on here because they either want advice as to the best form of HRT to start off and want recommendations or or they are unhappy with their current regime, very often because of the progesterone component. However, many women swear by Livial (Tibolone) for example and have happily taken it for years.
My advice would be to find a specialist who will agree to prescribe Indivina. In order to save both time and money, why not ring their respective secretaries and ask if they would be prepared to prescribe it?