Tempted to short EURGBP ?

Looks like it is in its final leg up (5th of a 5th) but where to put the stop/loss based on long term levels and on a previous high no-one agrees where it was is rather difficult.
Before heading back down the market seems willing to test the high of last October (when the £ flash crashed). Problem is to know where it was: 7 different data vendors have 7 different levels, ranging from 0.9141-50, 0.9225, 0.9256, 69, 70, 0.9326. Through the $ I even find 0.9433 as the top, so better use the highs of 2009, where more people agree, near 0.9410 and 0.9490-9500 to set the stop/loss on shorts. Always tricky to go against the trend, but a tiny short position can be tried near 0.94 with a stop/loss above 0.9550, which is pretty far away. If this is the end of the uptrend, the potential is huge though, sub 0.70, so reward/risk is more than ok. Plenty of time to add to this position once the uptrend is eventually broken, if the position still exists.