This is an over-the-top tough one to rival those two later Ardennes battles. Anyway, there are two problems I experienced with it. For one thing, yes, I suffered heavy casualties in the first Arnhem fight so I'm probably going to have to go back to that save and try it again with an eye on minimizing my losses. Having said that, however, there is still another problem that I'm going to need to work out even if I get a larger force. That is, it seems once the numerous German infantry move in to that line of houses to the north of your position, they are then able to easily suppress and destroy your defenders on the hilltop. With a larger force I suppose I could try moving in to those houses. However, as an analog I had two infantry and an MG in that row of houses to the south which I thought would have been adequate, but they were easily brushed aside by the German attackers. Anyway, I'm going to leave the game for a few days and come back to it latter with hopefully a fresh perspective. BTW, two 'aside' questions:
1) In #3 one of the things I did was made not losing any Piats a priority so that I could fulfill the extra credit victory condition. The result was that in #5 I had too many Piats and not enough regular Para infantry. So my question is this? Is there any benefit to fulfilling those extra credit victory conditions aside from bragging rights? If there is in the Market Garden campaign I've not noticed it.
2) In the first four campaigns the game seems to automatically remember your last completed mission, as well as allowing you to go back and refight any of the previous ones. With Market Garden though, I'm finding I have to go to the auto save to begin the next mission. Also, had I not already done a special save for #3, I would now be s.o.l. and have to go back to the very beginning.
... Achievement "carryover" is one addition that Pip has mentioned he would like to add sometime.
In light of what you said about the extra credit victory conditions, I will indeed replay #3 with an eye on keeping my losses down rather than fulfilling those bonus victory conditions. 
I keep going back and replaying #3 and I keep doing worse than the first time I played it, even though I now know more or less where the enemy troops are located. Go figure??? In my last attempt I lost my flamethrower; an absolutely essential unit to carryover to #5. Anyway, after playing the first four BA campaigns in rapid succession I'm probably burning myself out on the game and need to set it aside for a few weeks. Maybe it's time to go back to Panzercorp for a while, I see the first patch was released for it. Or maybe I should do a major gear switch and buy Slitherine's Hundred Years War game? 
