Just to follow up on this fare - the rules can be found at http://www.batraveltrade.com/cms/b2b...exi22Jun05.pdf - certainly not too many restrictions, the biggest being the MPM limitations (so roughly 26,000-30,000 miles, depending on the routing, as far as I can ascertain - but I'm sure others are more adept with the ins and outs of MPM).

Oh, and in regards to getting from South America to North America, BA helpfully has a codeshare from LIM-MIA, so there *is* a way to get between the two, and there's also a BA MAD-LIM codeshare too, so a couple of options for routing through Peru.