I was Semi P in the Coombe twin clinic 5 years ago so it might be different now. I had my 12 week apt & scan as normal, discovered it was twins & was not back until 20 weeks. Then it was every 3 weeks or so to the hopspital. After 30 weeks or so it was either the GP, Semi P clinic or twin clinic weekly. Some weeks I was up there twice. I was always scanned & weights were estimated. My DDS were ID so they were monitored closely. You can go public, My SIL was public there & was only 4 months behind me. I don't think there was a huge difference except for some of the appointments she ended up in the Public clinic downstairs whihc is bedlam.
As for delivery, my SIL had midwives only for most of it. It was her 4th PG & her boys were fraternal, she was also 39 weeks. Mine were prem, identical & I had a room full of people. It was a very different experience & I am not sure it was down to being Semi P, I imagine it was because I was high risk. DDS ended up in SCBU so there were paeds, gynaes, obs, midwives, students. It was manic.
An obs delivered, DD1 was by forceps. I think the rate of sections in Ireland for twin births is around 50%.
Any other questions, ask. I had DD3 there too a year ago exactly & I found the hospital to be great both times. I had complications both deliveries too.