Quick lands end stadium squall questions

[IAmSheWhoMustBeObeyed]

hi, I have one I got maybe 3 years ago (as recommended on here by cod). It is a petite in xs but pretty big. I am usually a size 10 and am 5'8".
So the coat is excellent but my knees get soaked as the rain dribbles down and hits the patch twixt hem and welly.
The questions are: according to the website the regular is another 8cm long, will my knees stay dry?
And should I get an S (10-12) or the XS (8)?
They are half price........

[IAmSheWhoMustBeObeyed]

Oh and the Tall version is also on sale but only in large sizes otherwise I would definitely go for that.

[cerealqueen]

Buy it, you can always return it?