I think you can only have gas at the birthing centre.
But full range of pain relief in the birthing suites in the hospital.
I had students present at my first c-section, but I had the option to not have them there if I wished.
With my second pregnancy I had severe Symphis Pubis Dysfunction. My GP kept telling me it was the aches and pains of pregnancy, the midwives were the same, then I walked into the Obs office at the hospital and he said 'ah, you look like you've got bad SPD'. I was so relieved to find out it was an actual thing and I wasn't being a crazy pregnant woman. He lined me up with Physio referrals and included a print out on SPD to go in my file. He said one of the benefits of using their hospital is that they are very up to date.