Thanks farnboroughrob and longshot. Based on files from the National Archives, the Swiss Federal Archives and an FOI reply, they travelled in small groups, maybe half a dozen or so. My focus is on people actually being deported after being interned for various offences, including one Swiss citizen (Victor Kronig) whose life I’m researching in particular, and who fell foul of the law for trying to bribe a police officer in Soho. The most direct route, via France, was obviously closed to them. However, nowhere is a mode of transport referred to, and I’m beginning to think they were, as farnboroughrob suspects, taken to Lisbon by ship. They certainly couldn’t afford the trip, as there’s evidence of disputes over who should foot the bill.