Result!

Being so close to Plymouth, it is quite possible to spend the day in France, while sleeping both ways on the ferry to Roscoff. All nicely arranged, 4 berth cabin with a window, taxi to the pub from Plymouth station. And the first night crossing of the year, just ready for half term.
Once in Roscoff (they took an hour to let foot passengers off: my idea was to be an hour late for the return ferry to pay them back, but our friends weren't convinced) we had to wait for their weird bus to take us to the terminal (it drives from both ends and is rather wider than a Devon lane: I can't see the Council buying one).

Roscoff was freezingbut it has a turkey, so that was alright

French railways are very strange: each passenger took about 5 minutes to get a ticket from the ticket window, as personal advice was offered for each journey: we bought 5 tickets for the price of 4, for instance, and gave one to the person behind us in the queue. The trains are very infrequent and seem to be replaced by buses at the slightest opportunity even if the train is sitting there at the station (which it was on the return journey). Morlaix is also lovely. It has a viaduct.

When we returned to the station, I bought all a drink, waiting for the others to catch up. I assumed they would think: "Where's Andy?" "He'll be in the bar". But no, I had to leave the drinks on the bar to go and fetch them. On the way out, M fell over a stool, and crashed through the door. The bar staff looked shocked, while only M and I cackled with laughter/embarrassment (it was her first drink of the day). The returning train was scheduled to be a bus (there was a train available, see above), which was full, forcing SNCF to find three taxis for the overspill, including us. Ridiculous. I got on the ferry early, the others stayed out in the freezing night.
The return was uneventful, and a lot quieter, the ferry lying stationary in mid channel for 3 hours.
On re-entering the land of my birth, the UKBA tried to scan my passport (never done it before: I flew 13 times last year with no problem). Wouldnt read the chip. Not on either machine. What a shame. Nothing to do with me, of course. A small victory for humans over twats.