As traviata says, the courts don't enforce automatically so it will be up to the aggrieved party to take action. If the ex seriously believes there is nothing that can be done to force the sale they are in for a rude awakening.
No, Bibbety means 8% pa but accruing at a daily rate.
The enforcement procedure is an order for sale and the court can, if absolutely necessary, sign the contract and transfer deed if the ex doesn't. Sounds weird I know and I only ever saw that happen once in the late 80's so it may be different now.
Even so knowing the person it will seriously piss them off if they have to pay more out!
Do you have any idea what the time scales would be if they do default and it has to go down the legal route? And how does it work if a sale of the property is forced by the court? It was put into the court order that if the cash wasn't forthcoming, the property would have to be sold.