You possibly have these references already? Numerous newspaper accounts of the mineral spring at Yarrow starting in 1846:
Saturday, Oct. 10, 1846, Publication: Preston Chronicle - detailed article mentions that it is on the property of John WILKINSON Esq.
Same item in: Wednesday, Oct. 14, 1846, Publication: Manchester Courier and Lancashire General Advertiser
Wednesday, Nov. 4, 1846, Publication: Manchester Courier and Lancashire General Advertiser - description of WILKINSON improving the access and sinking a well etc.
Wednesday, Nov. 11, 1846, Publication: Manchester Courier and Lancashire General Advertiser - description of 1500 people visiting, and medical cures. WILKINSON allowed the poor to drink for free.

Saturday, June 10, 1848, Publication: Preston Chronicle - detailed analysis of the mineral content of the spring.
Saturday, Apr. 16, 1853, Publication: Preston Chronicle - advertisement for "The Fountain" beer house with "Mineral Spring, Baths, Pleasure Grounds and Appurtenances" near the Yarrow Bridge, "late in the possession of Mr. H. C. Boothman".
Happy to send you copies if you haven't seen them.