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They actually reverse twice in each direction, once in the station and once on the approaches. In Loco hauled days they would propel into/out of the station.
In terms of the Republic services also reverse on route at Kilkenny (Waterford/Dublin services), Athenry (Limerick/Galway services) and Mallow (Cork/Tralee services, which then go on to reverse twice at Killarney)
They don't seem to be running at the moment. There is a London Waterloo-Yeovil Junction train a week tomorrow which calls at both Yeovil stations, but that goes via Warminster and doesn't reverse at all