Despite initial reluctance to make any comment what so ever (!) [member=144981]Orinlooper[/member] , I cannot resist.
I have absolutely no experience of Wales’ One Planet Development planning policy (as set out in the Welsh Gov’s Tech’ Advice Note 6), but would like to remark that it is refreshing to see a UK Gov’ taking environmentally-friendly development in the open country-side seriously for folk who seek to establish a minimal impact presence in this fair and still united, but increasingly overcrowded nation of ours.
Back to your Q: obviously it is not easier UNLESS one is absolutely genuine about embarking on a “One Planet” life-style and can substantiate that. Welsh Planning is not going to let this far-sighted planning policy become a loop-hole for folk to by-pass general open-countryside planning constraints !!