The amount of damage to the windshield changes from all over to mostly on the right side several times between shots during the chase with the police.
During the car chase, the Jackal keeps pulling the handbrake lever to slide the rear of the car around turns. He is driving a first-generation BMW 1 series. This car has rear wheel drive and if anything, is needlessly slowed down by that maneuver. You can just power-slide it around turns since it oversteers when accelerating.
Trevor's mobile home has a British number plate but the steering wheel is on the left hand side. British vehicles have the steering wheel on the right. - Foreign vehicles can be imported and registered with a British number plate, so this is quite normal.
Near the end, when the Jackal drives away from the home, the car keeps changing gears even though its a manual gearbox and he is holding the shifting hand (right hand) on the stearing wheel.
Since this was supposed to be his last job there was no reason for the Jackal to keep his special rifle. In fact of he had just thrown in it the sea he wouldn't have had to worry at the police checkpoint and could have easily gotten away.