It was suggested that maybe I should change the reaction to be something more towards disgust or envy (Thanks Scotts!). I agree that this would be the best way to go.
After sleeping on it and looking at the last playblast again, I can agree that it doesn't really make sense for Mrs Crawley to be surprised at the belt.
So today's plan is to:
# change the reaction from surprise to envy (I think envy would be best fitting)
# take out the jerk back movement - have Mrs Crawley's eyes follow Grandma's as she stands up before glancing at the belt
# add a couple of jabs at the beginning as per the reference.
And then hopefully I can put the whole thing into Splines. Hurray!