I believe its a sole agency without other branches (the opposite is multiples, agencies like Lunn poly or Thomas Cook where they have multiples branches)
thats wrong sorry but miniples are travel agents with 5 - 50 branches - independants are travel agents with 1 - 5 branchs - and multiples are the larger travel agents such as thomas cook you can find a miniple travel agent usualy ituated near a high street but not quite on the highstreet they are the lesser known names and usually all branches are situated within one region hope thats helpful