I got to watch it after finally managing to download BBC iPlayer desktop... after the internet connection kept stalling...
Overall I'm loving it though do wish they'd made it rather longer, there's so much to cram into 3 episodes.
I was delighted to hear of Anna Maxwell Martin being cast as Sarah and still am, she's excellent, if she and David Morrissey are both a tad young IMHO. Was less sure of David Morrissey, who I didn't think looked quite the part for Carne (i.e. not craggy and saturnine enough) but am won round. I think he's really captured that combination of stubbornness, tiresome not to say stoopid! prejudice, love, sadness, careworn air. And wasn't he gorgeous in the calving scene... I did wonder for a moment whether he was going to take his vest off too a la Darcy diving into the lake 
. I also really like that he has a Yorkshire accent instead of some off the peg posh accent.
I'm liking Douglas Henshall as Joe Astell but I do wish he wouldn't keep reminding me somewhat distractingly, in certain lights, of Julian Assange.
Not quite so sure about Penelope Wilton as Mrs Beddows, meaning I suppose that she doesn't chime with my own image of Mrs Beddows, who is slightly older and more Edwardian. We don't get to see any of her (not always happy) family life, which I think is a loss.
Not sure about Maythorpe Hall either. OK it looks like an old fashioned squire's house (which is exactly what it is) but not one that Muriel ever got her hands on... if I'd been the set designer (which clearly I ought to have been 
) I'd have decked it out in oodles of sad, faded "Titanic era" splendour. Muriel would have had no truck with all that ancient dark Jacobean looking furniture!
Goodness, what a waffly post, please excuse me 