Where can I get a Casio fx991ex calculator for A Level Maths?

Hi everyone, like the title says I am looking for a new calculator as I was told my current gcse one isn’t sufficient for the A Level. I know Casio has released a new fx991 calculator, but my teachers says it isn’t as good as the older model fx-991ex. I’m in the uk and haven’t found any sellers and most ebay ones are fakes, anyone know any reliable stores in the uk or ones that ship here? Thanks!