Further to BL-and thanks to him for the unravelling of those companies:
they now also have an office in BKK-Viengtai HTL, near Khao Sarn.
I once spoke to a guide of those tours with a beer or 2-and he told me, nearly half of the subscribers skip somewhere during the cheap Gecko/intrepid tours as they find it more adventurous and discover that in Thaild/Lao etc it soooooooooo easy to do on your own, even for nervous 1st time types.
There is also STRAY adventures, offering moreorless same-same, and also all types of bike tours around and in BKK-brand new ofice on Ratchdamnern, also close to Khao Sarn. I thuink this is NZ. They run own minibuses in Laos between major tourist places, like they do in NZ.