Two points for you to consider:
1. treat that initial roll as you would the first part of a slow roll - roll quickly to 60 deg bank
2. the turn has a very low K factor so it doesn't matter a whole lot if its not perfect, not that I'm sugegsting that you throw points away but use it to maximise points in other areas i.e. what figure is next? do you need to descend during the turn to exit at a particular speed? where are you in the box?
There is simplified judging criteria at
the BAeA website