Baptists in Helmsdale in the 16th century

I have been informed that a book published in November 2007 indicates that as well as baptist being in Leith, Ayr and Perth at the time of Cromwell, that there is a strong case that English baptists were in Helmsdale at a garrison around 1650.

I would appreciate any information that would tell us a bit more about these soldiers in the North of Scotland... 200 years before the disruption.