Yes I agree too. The fact that it is heavy bleeding is not explained by just missing one dose of HRT. The heavy bleed means that there is lining to shed (following the missed dose). Theoretically on continuous combined HRT, if you are post-menopausal, if the balance between oestrogen and the progestogen is correct, no lining should build up, so that even stopping the progesterone should not cause a bleed. If it does, either it is due to your natural cycle breaking through, ie not fully post-menopausal, or the hRT balance is a bit off. The doc will be able to check this for you and if necessary adjust the HRT?
Hurdity x