Consensus is a bit higher than that Gordon.
http://markets.ft.com/research/Markets/Tearsheets/Forecasts?s=GBT:ASX
Only 6 analysts, but 5 have it as Outperform or Buy and highest target is $6.10.
Not sure who is buying but a strong breakout above $5 has occurred.
Think $5.20 targets will be very shortly amended. IMO