I do some of the ordering for the regimental clothing stores of a military highland regiment, in cooperation with the RQMS, Fin O, and other appropriate agents of the Regiment. Not sure if discussing procurement in open forum is permitted - not because anything 'bad' is going on, but because of the seriousness with which DND takes the entire process. We've all done some training courses recently reinforcing the need to properly tender bids, etc.
I think I am safe in saying publicly, though, that we have dealt with Burnett & Struth as well as L&M Highland Outfitters in the past and indeed have noticed the quality of their work, and speaking as a private individual, not a member of DND, would second your opinion of their work. Not just because it looks good, but because higher quality kit lasts longer. We have a high turnover of equipment - you mention spats. We bought some spats from a well-known highland outfitter who was known to outsource his work to Pakistan, and as noted, got what we paid for - his wares were replaced in less than five years if I recall correctly.
Why is this applicable to a 20th Century/re-enactment forum? I guess there will always be a debate as far as how close is "good enough", particularly for re-enactors or reconstructions, and what the purpose of your reconstruction is. For deep background film-work, I don't think you particularly need the best and most-expensive kit available, nor necessarily for "mucking" in private shoot-em-up events. For public displays, photo-shoots, or hands-on events, or for getting into a hobby you intend to be a part of for many years, as you note, the extra investment will pay dividends.