I doubt this will be the last show he does. The last season, yes, but not the last show he'll be in. I get the impression with the growing backlash towards Bear Grylls...they'll hire Les as some sort of presenter for other shows and/or specials.
You bet. Les' special on Sharks is only the beginning. The Survivorman series gave him is "break." Now, Les is well known as being the credible survivor guy, and he'll be doing a lot of intereting shows. In the article I read, it said that Les wants to follow in the tracks of famous explorers, which should make for some good viewing.