Red Bull allowed reserve driver Liam Lawson to get behind the wheel of their RB20 at Silverstone last week. While nominally a filming day, it allowed the team to evaluate him amid the uncertainty around Sergio Perez. Lawson’s mileage was restricted, and he wasn’t able to run standard Pirelli tyres. Nevertheless, Red Bull set him a benchmark based on Max Verstappen’s pace at the British GP weekend. The New Zealander reportedly fell around two-tenths short of that target, leaving Red Bull engineers underwhelmed. This may hurt his chances of replacing Perez in the second half of the season. Perez…