I know of nobody in the UK that breeds this species and sells them publically, but a few zoo's have them. If you see them on shops livestock lists they're very likely to be labelled wrongly, large female guineti can be quite colourful and i can see why people might get them confused but the antongilii really are stunning. They're a CITIES appendix 1 animal and were readily available until, well, i've not really seen them around since the mid 90's where they used to go for around the £60 mark. This is not to say that some antongilii aren't floating around, it's just it's highly unlikely. Maybe try the Hamm show?.