Hi @RO31,
Do you know which model of Xperia Z that you have? For example, C6603 supports LTE bands 1, 3, 5, 7, 8, 20 which can be found in the white paper: http://www-support-downloads.sonymobile.com/c6603/whitepaper_EN_c6603_xperia_z.pdf
Depending on the model however it may not support LTE, so for me to check for you I'd have to know the exact model. The model can be found under Settings > About phone > Phone model.
