Hi Oxa,
Thank you for getting back to me.
It seems you can cancel bets while the market is suspended. It's only recently that I've wanted to do this, so I haven't noticed before. It seems that if the market is marked to go in-play and you fire a bet with persistence on (otherwise it'll be cancelled automatically) when the market is idle, but when the event starts, if the market doesn't then go in-play, you can cancel the bet.
I've confirmed this in football, where I've had an umatched bet once the game has started, it was supposed to go in-play, but just remained suspended. I can see the bet in the Betfair web interface, but I can cancel the bet in the MFP interface and it dissapears from the Betfair web interface (without any interaction in the Betfair web interface) and the funds are then added back to my available balance. The market is still suspended after this.
So basically, I can cancel the bet in the MFP interface, from the list of unmatched bets, but a trigger won't cancel it.
I hope that makes sense. Let me know if you need any more.
Reggie