So I compared the L'Amant ink against a few of my purple inks (Noodler's Black Swan in Australian Roses Version 1, Version 2, De Atramentis Purple Violet, and Diamine Pansy). Aussie Roses version 1 was leaning too red/brown and Aussie Roses version 2 had the right kind of purple but had muddy tone which didn't suit. De Atramentis Purple Violet was the right kind of purple too, but because Diamine Pansy was similar and was made by the same brand as the other component of the mixture I was going to use (Hope Pink), I went with Diamine Pansy as the base ink to mix the Hope Pink into, to try and get colour of the mixed ink as close as possible to L'Amant.
So I mixed 1 part Diamine Hope Pink to 4 parts Diamine Pansy and the colour is similar to L'Amant, but now that I look at the photos in detail I think I could have added a little more Hope Pink in the mix to shift the colour pinker. Perhaps I will test it again next time as I am still curious about paper chromatography test of the mix.
Diamine inks are relatively easy to get a hold of and now that the Pansy ink is available as an individual bottle rather than as the whole Flower Set, the components of this mixture are much easier to come by compared to the L'Amant ink itself. The colour can be made to be pretty close to L'Amant, but the ink's behaviour and flow characteristics are of course different (Sailor vs. Diamine) and therefore shading quality is different too.
Anyway, here are the photos. I think I need to add a bit more Hope Pink to the fake L'Amant so I will keep working on it. In all the writing samples, only the same pen with same nib unit was used, and between the ink swaps the pen was flushed thoroughly and nib unit was ultrasonically cleaned.
L-R: Sailor Bungbox L'Amant, Diamine Pansy, Diamine Hope Pink
Upper half is written with Fake L'Amant, bottom half is genuine L'Amant.
Pen: TWSBI 580 Rose Gold with vintage Waterman #2 Canada 14K nib and ebonite feed from FPR
Ink: Sailor Bungbox L'Amant compared to a mixture of Diamine Pansy and Diamine Hope Pink
Paper: Tomoe River (White)