As the victim of Rosiglitazone, now thankfully withdrawn from the market, but closely related to pioglitazone, this news beggars belief. Pioglitazone has been withdrawn in France and Germany because of the high risk of bladder cancer and even in the U.S. it carries a health warning that using for more than a year there is a risk of bladder cancer.
The only good thing about NICE is that they recommend to GPs that any drug they prescribe must be done with the agreement of the patient. So, we just have to make sure patients are aware of the issues and also that they have the right (for want of a better word) to refuse any drug prescribed.
I've noticed that Metformin doesn't seem to be automatically prescribed in the Sustained Release/eXtended Release versions. It would seem that you have put up with the worst diarrhea imaginable before the GP will prescribe the substantially more expensive versions. That in itself is a con because it's not rocket science, they just add a gum to slow things down.