Ah, the joys of doing 37419 on that service back in December...Must have been the only one on this forum who did them! You lot missed out on the return run, which was quite enjoyable, compared to the 42 (or was it 47?) down arrival at Fishguard. Left 35 down, arrived 11 down at Cardiff.
Back on topic, a 143 on the 1055 is not common, I must say. It's been run by 158831 a lot in recent weeks, and is usually a 158. Stock availability must have been very low, especially with the 175s, for a 143 to be found on it!
And for the chap who asked, it is 2.25 hours usually. Why it has to go via the Swansea District Line, instead of taking the faster route via the Swansea avoider line running round the back of LE I don't know. Could chop off at least 15 minutes going that way, but hey, must be some reason.