Casting

Taking a glance at the message board suggests that I probably won't get a reply to this, but what is up with the cast changes in Sharpe's Honour? Both Major Hogan and General Wellsley (Lord Wellington)were played very well, probably to the extent that they were my favorite parts of Sharpe's Eagle and Rifles. I also thought the character of Captain Lloyd was pretty good, we Americans don't often see mention of those of us who didn't come along for the ride. He was an honorable and competent character who still ended up at odds with Sharpe. So what happened to Major Hogan and Captain Lloyd? What happened to the actor who played Wellington? Is any of this explained in the books?