Fan artist recognizes gap in the series
Kill La Kill makes a brief return in September in OVA episode 25, set to be released with volume 9 of the series. This is apparently a graduation episode, which suggests that there won't be swimsuit or hot springs episodes. Recognizing the gap, fan artist shinonoko has filled it in with a bit of their own hypothetical beach ep.
Also by the artist...
Fan animator @Shiika_Sadamasa also put together a bonus scene