Hi
In Connection Monitor, you can view the statistics for your current bets refresh.
But it will be variable depending on internet connection, country of origin, internet routing path, state of Betfair's servers, time of day (3pm Sat during football season etc.)
You can write a small trigger which will place and cancel bets outside of range e.g lay at 1.01 and cancel, back at 990 and cancel.
Add a second action to the betting trigger to write to action log now_time
and then in the Program Log compare the timestamp for the bet (which indicates if it was matched or not) to the now_time entry.