Hi Sam,
Technically good (to my inexperienced eyes), with the exception that I think it would stand 1/3 to 1/2 stop more exposure. I know without a peak white in shot it is easy to over expose skin tones, but I think this is just a little too cautious - you might need to apply that just to her face and hold back the tree trunk though.
Looking at the shot as a whole, I would have excluded, or cloned out, the tree trunk in top left corner. Also, there's a brighter background patch below that trunk on left that I'd dim down some more.
Also (2) there's a bit of patterned shirt/jacket extending right down to the lower edge of frame that pulls the eye down there and out.
It looks like you were both having fun on the shoot, so well done on getting a good relaxed expression from your model and the balance of flash and ambient is very natural, with no dark shadows either.
Personally, I'd score it 8/10, but I don't
do portraits

and I certainly don't have your skill with flash, but I can appreciate the result
Cheers,