Both are weak currencies. If you don't understand, then DO NOT TRADE this pair. It is VERY volatile with high pip spreads. Newbies.. do not trade this kind of pair. They stick with the majors, like xxxUSD orUSDxxx.
Fundamental Risk: Today's event release can totally make or break this. However, if the release is bad, I think this is already factored in, given the Brexit. It is as though the fundamentals do not matter at the moment. Everyone knows that it is bad news for UK, it is time for covering. At least for GBPNZD a few 1000 pips or so. Like I said, this is a more riskier trade than normal.
Given the strong downtrend line, I don't expect this to be a winner; but, if it does break about it, then the relief rally begins before the UK rate decision.