Well done Galadriel! What a fantastic GP?
Which leaflet says start when you like? Also presumably you are taking the HRT cyclically ie 14-16 days oestrogen and 12-14 days Provera because you are still having periods?
If that is the case then I agree with silverlady that it's best to wait until your period - but if they have been irregular then you may well be out of sync (ie HRT with your cycle) and experience bleeding at odd times - but might as well start in sync!
If it is 14 days per 28 that is quite a high dose of progestogen for a low dose patch, but if you are peri-menopausal, have skipped periods and some are very heavy, then the extra progestogen at this time will probably help control the bleeding.
As a matter of interest Any reason why you and your doc chose Provera over Utrogestan?
If your period does not arrive within a couple of days of the expected time I would just go ahead and start.
Hope it goes well!

Hurdity x