Thanks again for the replies guys.
Fressia thanks for the positive words ! Mum is currently on lucentis and that was the drug the medical review officer used to predict her ongoing costs. If she is switched to avastin, as you mentioned a commonly used drug for her condition, she would come under the medical costs threshold. So we where surprised she got knocked back after we asked for a second medical review looking at avastin, but realised it's not done on her individual situation , it was done on a hypothetical case on the more expensive drug.
i understand some of the logic but how can you assess an individual's medical costs if you are not looking at the individual themselves and looking at a hypothetical case ? That's the frustration !