The most I can find on the tartan comes from the Scottish Tartans Authority website, which says the Ben Lomond tartan is "[a]n ACS Clothing sett for their kilt hire business". After a bit of searching, it appears that ACS Clothing Limited is the same company as Cameron Ross Limited (http://www.hirewear.co.uk/). The outfit builder on their website does have the Ben Lomond tartan, so it's probably them. If nobody here has the answer to your question, I suppose you could try contacting Cameron Ross. Their customer service number is on the lower right side of their outfit builder.