Takes a while but it works!
Cat has been on this for a year now. Initially didn't see much change and wanted to give up but persevered. Now a year later cat has gone from 6.2 to 5.6 kilos which in cat terms is a good amount of weight to lose. She also loves the food and hasn't got bored with it. Very happy and going to continue though it will possibly take another year on the 'diet' for her to reach a 'normal' cat weight. She is already more agile and is jumping with more ease which is good to see.