Sorry to just catch up with this
@Harms88 - that spa was on my LIST ( which is getting longer, we're busier than ever with the lockdown ) . You may not find anything via Google search? Those spas were amazing, generally wonderful, sprawling hotels slash veritable mansions where people flocked for vacations. Try era newspapers entering but don't use ' spa ', use ' resort ' or ' hotel ' or ' mineral springs '. You'd also have luck browsing those lengthy pamphlets railroads produced- they put together excursions inclusive of those places.
I ' think ' I might know which one it was and never knew they'd turned it into a hospital- poked around in those places not long ago.