I couldn't get my hands on the low-salt one either, but I would assume that so long ad you compensate with a bit more water, the salt shouldn't make a diff.
The shop I was in had a regular or a vegan option of the marigold bouillon. I picked vegan coz the other one has lactose ... Seeing as we're not allowed milk I figured it was the safest option... Mightn't make any diff though.
It's such a relief mid-morning to have it. Yummy and warm.