You'll be sick of hearing from me.
To have a "bet history" the only way i know of is to write code that will copy the data to another sheet - probably when the race becomes suspended (after being inplay). I'm afraid i haven't written any code to do that.
For the Bet REf, it may depend on whether the bet is partially filled (i think)
i would suggest using =""
so that there is either a bet ref or there isn't.