Now you are mixing metaphors. The original IPA's were brewed in London. I think it was Hodgson's Brewery or something like that. They likely obtained their water from the New Canal (I'm going from memory) and that was a surface water source that skirted the north of London. It was not likely to have been that mineralized.
IPA brewing subsequently shifted to Burton where the mineralized groundwater was ideal for hoppy and bittered beers. Depending upon the source and conditions, the groundwater could range from highly mineralized to modestly mineralized. You can see the results of recent groundwater testing by reviewing the Burton profile in Bru'n Water. However, it is unlikely that the local brewers used water that was that highly mineralized. Depending upon where the breweries were extracting the groundwater from, the water was either naturally diluted with water from River Trent or the breweries manually added river water to the groundwater to reduce the mineralization. It is therefore more likely that the water quality used for Burton brewing is similar to the Pale Ale profile given in Bru'n Water. I recommend that you start with that profile to help duplicate the second "original" IPA you are attempting.