You've got what looks like a great assignment. You'll probably be part of a team. I hope that in this case, the word "Team" isn't what it often is in business: A euphemism for "Hornet's nest." If you're working alone, I hope you get to go back and forth with Big Mak. I don't know his comfort level with speaking English, but he appears to understand it very well. He quotes from many excellent sources, including Barbara Ehrenreich's then ten year-old commentaries about the yuppies' tenuous place in the economy.
I hope you're able to do a good translation. Translations are often marketing. Books can have different tones in different languages. I wonder about Hoe God verdween uit Jorwerd, which I think is best rendered as, "How God Disappeared from Jorwerd." Instead, the English title is watered down to Jorwerd: The Death of the Village in Late Twentieth-Century Europe. The original angry title is now very academic. I think it's fine if the author didn't have a title at the beginning, but if the first one was his title, his point of view has been changed to increase sales.
For the British edition, it might be ok to leave the everything alone. British audiences are familiar with European politics. They have proximity to the Netherlands, and they should have a fair amount of prior knowledge.
For American audiences, be sure to include maps, timelines, and plenty of footnotes explaining acronyms and other things that are not well known here. I remember searching for something that turned out to be a reference to a brand of cookies. Although it's a serious book, memoirs usually have more pictures. A couple of picture sections would make it more accessible to those thumbing through it in the bookstore. Also, you might have to explain Catrinus Mak's postcard in English. An American audience is likely to assume that the original card was in Dutch and written over with Photoshop.
Finally, you should be part of the book's promotional efforts in the US, even if the author speaks English well. I remember catching Octavio Paz and his translator Eliot Weinberger on tour in 1987. I enjoyed watching their interaction. Both translators and authors have stories to tell, and it would be worthwhile to hear about the process.