From The Military Discipline wherein is Martially Showne the Order for Drilling the Musket and Pike, published by Thomas Jenner, London 1642. This is plate five of the drill book published just before the wars broke out. I’ve no reason to suspect this is anything other than portraits of the trained bandes of London at their postures. These guys are dressed in high status clothes, braided breeches and slashed sleeves. Not the kind of clobber you would wear to take the the field.
The style of the plates is very similar to a drill book published in Europe in 1607 with engravings by Jacques de Gheyn. In fact there are a number of european and english drill books starting from de Gheyn, using exactly the same poses but every time updating the clothes.
More rear views here, number 13 is wearing a montero cap and interestingly number 16’s coat has no back seam, and is slit to the waist, something that would only really work with a well fulled broadcloth that wouldn’t fray easily along the edge. 15’s coat in contrast looks like it is hemmed.
This is number five in the series. I took the photos from the original book.