If the GBP/USD is indeed in awave4, then price will bounce at the Fibonacci retracement levels and continue for a lower low. vs 1. A bullish break above the 50% Fibonacci level makes a wave 4 pattern unlikely and increases the chances of a bullish ABC pattern (red) rather than a 123 (purple).
The GBP/USD seems to be completing an ABC correction (green) within wave 4 (blue). The Fibonacci levels and the support trend lines are key.