GBP/JPY failed to take out 125.82 resistance last week and dropped sharply since then. But downside is so far still contained above 122.86 minor support. Initial bias remains neutral this week with focus on 122.86 minor support. Break there will indicate completion of the corrective rise from 118.82. In such case, bias will be flipped back to the downside for retesting 118.82 low first. On the upside, though, above 125.47 will extend the rebound from 118.82 to 127.10 resistance and above.
In the bigger picture, there was so far no impulsive upside move after GBP/JPY formed a medium term bottom at 116.83. On the other hand, there was no sustainable selling neither. The development argues that even though there is no clear sign of trend reversal in GBP/JPY, it's more likely engaging in sideway consolidations, which corrects fall from 163.05. That is, we'd probably see more range trading between 116.83 and 140.02 (50% retracement of 163.05 to 116.83 at 139.94) ahead, before an eventual downside breakout.
In the longer term picture, fall from 251.09 is treated as resumption of multi decade down trend. Current development gives no indication of medium term reversal yet and GBP/JPY would likely drop towards 100 psychological level on down trend resumption.