A few days off work, a few bits of wood and 22mm copper pipe left over from my last DIY project and voilą, one home made, portable high seat (it actually only took just under 2 hours to knock together). Just needs treated against the elements and we're done!
Comes in 2 handy sections, ladder + seat, easily thrown over the shoulder. The shooting rail is approx 3.3m from the ground. Might not last forever, but good enough for me for a few years.
(gaffer tape used in prototype, will be using proper straps when used in anger)
(unfortunately I never did get a PD Highseat ordered, couldn't quite sneak it past the Mrs )