Correct. Well done.
The signal is a summersault type with a pivot in the middle. I hadn't noted it lacked a number, but it seemed to be just protecting the crossing along with one on the other side and corresponding distance signals).
This is what it looks like in the off position.

I didn't notice the class number but "
CAF▸ " was the manufacturer on the makers plate inside so you are probably right.
No ticket machine at the station means I boarded intending to buy a ticket from the guard. But was I to ask him for a return to Derry or Londonderry (I prefer to stay neutral in other people's arguments)? I decided I would avoid the issue by asking for a ticket to "waterside station" or "the end of the line", but in the end he didn't come round I was able to buy a ticket on arrival "from Castlerock"

Waterside station