Hi Keane

If you have had a hysterectomy then you don't need the progestogen any longer so if you would like to re-start HRT, then I suggest you ask the doc for some oestrogen only patches.
If you have only recently had the hysterectomy, and retained your cervix, sometimes a progestogen is given to checky there is no uterus tissue. If there is no bleed then OK to continue without progestogen.
Depending how long ago you had your hysterectomy, and whether you were taking HRT immediately before that, there may be some resistance to resuming HRT, but if you feel you would benefit and are having menopausal symptoms still, then I would ask your doc or gynae!
Hurdity x