Update:
Just hours after the last post, the cap broke down. Lol. There really was a price to pay. It was replaced with a new one with 250V rating and now it really works. Only goes to show that thorough testing before putting into practice is fundamental. Which was by the way exactly what was done 
After having the new fencer on for a week and teaching the pigs how the fence works - indoors with no chance of escape! - they were led to an outdoor pasture surrounded by an electric fence powered by the fencer unit and live a happy outdoor life.