Blood test shows some improvement

Urea down significantly, from 27 to 17 (top end of normal is 9.6). Creatinine (which tends to lag by a week or two) is slightly up.
Phosphorous is still normal (this imbalance is the bit that tends to make them actually FEEL ill).
Potassium is a bit low (which can create muscular weakness), so Fiona will give us a supplement for that.