I've only just caught up with this thread and send good wishes for Eliot and healthy blood test results.
My eldest Siamese, Cleo, has mild hyperthyroidism and has responded well to mild medication. I hope this isn't the case with Eliot but if it is, take heart. There is lots of info on the internet and I can help you find it should the need arise. Let's hope for Eliot's and your sake that it doesn't.
Keep us posted, won't you?