Much better episode, with more cracking acting.
Fatty is being a spoilt brat about the estate management. THIS PARTNERSHIP THING WAS YOUR IDEA, DICKWEED.
Dowager was funny about lying with Clarkson. We have had far too few scenes with just her and Fatty - her as a mother, rather than a MIL and matriarch IYSWIM. More please, she is far more interesting like this.
The Ethel lunch and Isabel being surprised by how good it was was funny too. I thought Fatty was going to assert himself more - it would have been interesting if he had involved Matthew, which logistically he should have tsk tsk. Would Matthew have agreed with Fatty and tried to give Mary orders, or would he have condoned his mother's ideas? He is a bit of a stick-in-the-mud, for all his modern farming ideas, and of course achingly middle-class, so I think realistically he would have been just as catsbum as Fatty. Opportunity missed.
I thought Daisy might become her own mother-in-law, yes. Good for her. Nice little tea shop for visiting DA staff. The thing about would DA be the same in forty years (1960s, ha!) was interesting too.
Now, forgive me if I am well off but didn't Fatty have some clandestine snogs with a maid in series one? The married/widowed one who left and was replaced by Ethel. I think he may actually be pissed off that he didn't get an opportunity to exercise his droit de seigneur and maybe she even tried to charge him 
because the look he gave her and the look she gave him ... Du lieber Gott!