Behavior at the yellow box will tell us the magnitude of the correction. A quick bounce off the red/orange line indicates bull strength. If price penetrates deeply into the yellow box we may visit the 3600 area before long. The top holds some significance from the 2000 levels but I think the round number is likely what's holding it down (you'll notice it went over...
I plotted all GBP pairs and narrowed it down to this. EURGBP which appears to have the highest correlation (no surprise there) and GBPJPY which appears to lead GBPUSD the most effectively. If this pattern is anything but coincidental I imagine we can expect a consolidation on GBPUSD similar to that seen on the yen (long and flat and long)
To me it seems that the spot natural gas should provide more valid historic s/d levels than the futures. This chart raises the question, though potentially in an ambiguous manner since both the spot and futures have levels at this area. The level held extremely well, suggesting that overlapping levels may hold a secret mystical power.