Hi Puzz
Next time you need to drill acrylic, try a brad point drill bit.
Here's what it looks like. Drill a pilot hole, move up to a bigger brad point drill and you'll have no problems.
It must have been really touchy doing it with a regular twist drill. A little too much feed rate and your top is toast.
If you've got a grinding wheel with a sharp edge, you could grind a drill yourself. Just make sure the distance from the center of the drill to the edge is the same on both flutes.