I just happened to be playing Bags and Trade (45) - I'm pretty sure it's Analogue Productions and it's squared off with no "lip", but it still makes a little pop when the stylus enters the groove.
I know you are big on vacuum/suction @mijostyn , but for those of us who want the minimal vibration transferred to the record from the platter, you don't want the mat going to the edge of the record. The mat I use is hexagonally shaped (called the eclipse Hexmat) and doesn't reach the edge of the platter even at its 6 outer points. They also have a cheaper one called the Yellowbird I think, which has a little more contact surface area between the mat and the record.