Are there any Brits on here who have built successful careers in planning abroad or have worked abroad for a shorter amount of time?

My career plans have always anticipated a period working abroad, but I'm wondering what is the best type of experience to gain. I am about to move jobs so have some degree of choice about who I work for, so the question is who if I want the best chance of working abroad in an anglophone country?

I already have local government experience in rural planning and am looking at several London based planning consultancies (private sector). The difference between the consultancies is whether they are "pure" single disciplinary planning consultants (working with a variety of private clients on applications, Environmental Imapct Assessments, appeals etc on major projects and some public sector strategic work), or more multidisciplinary consultants (design, surveying etc) with a larger emphasis on regeneration work (public and private sector led), again major projects.

Any advice gratefully received on what would be a good thing to focus on for a few years with a view to working aborad.

Does RTPI membership mean anything at all to employers abroad? I'm guessing it might in commonwealth countries that may have similar planning systems to Britain?