A short below 2700 itself, IMHO, was permitted. Either, below the low of the breakout bar or if price would have gone below the retracement bar.
BTW, now as price is inside the channel one again, one can look forward to shorting at the upper channel line with an assumption that channel will not be broken. Ofcourse, divergence alongwith candle behaviour, at that point, would come as a handy tool. If, however, channel is broken on the upper side, the short trade should be reversed.
Regards,
--Ashish