Selloff from the top doesn't always goes on the first attempt, so dont be discourage if the trade ends at a BE.
What may trigger this pair to go down:
1) U.K Prime minister may fail to secure a good trade deal with the Eur zone, especially if she cant get a deal for the U.K financial industry to act in the Eur zone.
2) Aud may plunge down, making the GBP to go up relatively.
Trade with care or dont trade at all.