I emailed Lorne at Race Technology about the DASH2 freezing. It only seems to happen when it's not connected to the laptop.

Lorne replied and said that Westfield should have sent me a terminator that should be connected to the dash serial port when not connected to a laptop, and he has popped one in the post for me. Until it turns up, I'll just make sure I connect the laptop to the DASH2 when the engine is next running.