Am I missing something? The police had CCTV of outside the club which captured Adam and Aaron running from the car. Surely this CCTV would also have captured Donna and Ross (dressed in a police uniform) entering and leaving the club, and yet the focus is on Adam and Aaron. I'm confused.

That's a good point

However, the police in Emmerdale are very thick so as soon as they saw Aaron and Adam on the CCTV they probably thought to themselves that they had found the suspects so they turned the tape off after that

Ross in uniform. phwoar