@alexhaydock a&a is awesome. it's the only isp that i'd ever use, to actually route my traffic.
the physical ISPs that i have at the lab, i simply regard as transit ISPs, for hooking me up to a&a - that's what the l2tp is for.
also: xl2tpd (which i cover in my guide, and so does the other guide) was ported to openbsd ports, and the person who ported it is an a&a user!
they also have openbsd routing guides on their wiki:
https://support.aa.net.uk/index.php?search=openbsd&title=Special%3ASearch&wprov=acrw1