As well as gold and silver from Charlie-Joe Hallett, para-swimmer Whitchurch performed well to medal in the 200m freestyle – one of four multi-classification events she competed in.
Whitchurch had set new personal bests in all of her swims, as well as reaching the finals in each.
Categorised as S5, with S1 generally indicating the most severe activity limitations and S14 the least, she competed against a field of swimmers in her class to S14.
She gained enough points to make the finals and went on to finish ninth and 10th respectively.
With the 50m backstroke being limited to competitors from the lower classifications, Whitchurch took on a solo time-trial and needed to break the British record to medal.
Despite finishing in a new personal best of 55.21sec., she was three seconds off the record.
Although disappointed, she put this behind her and finished the meet on a high, claiming third place and the matching medal in a 200 free race where she shaved four seconds off her entered time with a new PB of 3-50.50.
Whitchurch will have another go at the British record at the Para Nationals, to be held in Manchester in December.
Meanwhile, Hallett topped off his earlier 400m individual medley silver and 200m breaststroke gold with his final two swims of the week.
Over the 50m back, he finished just outside his PB and in 12th position.
Making the final of the 200IM, he gave it his all to finish in a new PB of 2-09.74 and fifth place.
Adding to Guernsey’s success in the multi-day event, freestyle sprinter Jonny Beck came just short of bringing back a medal for the Barracudas.
In a close series of finishes, he swam a fast 23.59 to wind up critically outside bronze but with a new long-course PB for his result.