Macy Lawrence led the way in Sheffield with gold in the 16-year-old girls’ 50m butterfly event.
She clocked 28.76 seconds to take the crown. Danish swimmer Julie K Svendsen did win the final but was swimming as a guest and so was not eligible for the national title.
There were also silver medals for team-mates Maxwell George and Jacob Newcombe.
George’s podium place came in the 15 year-old boys’ 200m backstroke, where he clocked 2:12.77.
Newcombe’s silver also came in the 200m backstroke, but his was in the 17-year-old boys’ category, where he clocked 2:06.90.
Fellow Mount Kelly swimmer Sophie Main and Plymouth Leander’s Finlay Washburn also made finals on the last night of the meet at Ponds Forge.
Meanwhile, Mount Kelly College’s Federico Burdisso impressed at the European Championships in Glasgow.
The 16-year-old, competing for Italy, just missed out on reaching the 200m butterfly final.
Burdisso, the youngest swimmer in the field, clocked 1:57.39 minutes in the heats to secure a semi-final spot.
He went quicker in the semi, finishing in 1:57.10, to take fifth place in his race. However, he was ninth overall, so just missed out on the final by one place.
It did look like he was going to book a place in Sunday’s showpiece event in Glasgow. He swam a stunning 25.71 seconds for the first 50m and was second at the final turn, but he just tired in the final few metres.
Former Plymouth College pupil Ruta Meilutyte did reach the final of the women’s 100m breaststroke – the event she won Olympic gold in back in 2012. She also finished eighth in the 50m freestyle in Glasgow.