Sorry it's been so long to update, the soup was delicious despite my bungling.I had to use dried thyme instead of fresh and since we didn't have any lemons or lemon juice (I wonder who's fault that is) I bruised some lemon grass and threw that in.
I had forgotten to add the thyme until the end, so the first night we had it, it was very 'thymy'. Leftovers the next day was much better as the thyme had a chance to blend.
The soup was a bit fibrous but that was my fault because when I asked Mr. Qwerty to use the immersion blender (I was fielding phone calls from panicked parents because Kate had decided to make her party a costume party and didn't tell me), I forgot to tell him to fish out the pieces of lemon grass. Lemon grass stalks don't puree well (learned something new today), but the soup was still delicious and very edible.
I can't wait to try this again but properly this time.