In early June we're intending to visit friends in Pembrokeshire then take the ferry from Fishguard to Rosslare. A couple of weeks we will sail from Larne to Cairnryan. Do we need to book both, either or neither? Will it be ruinously expensive compared with advance booking? We have a 5.2 m van. Being retired we'd like the flexibility but if needs must we will book. We always used to book as work didn't allow for any flexibility and it's a number of years since we drove abroad. Later we're planning to take the van to the Netherlands via Newcastle.