I assume you are talking about a possession order for your house. The answer to your second question is that - provided they follow the law correctly - they can get the Court to order that the house is sold. The mortgage and any other debts secured on the house prior to your bankruptcy would then be paid off and the remaining money go towards the OR's costs & your creditors. If the result was that all the OR's costs & creditors were paid in full the remaining money would come to you.
The value for the house they use when they decide whether it is worthwhile going through this process is the current value - not the value when you became bankrupt.
As regards yuor first question, you will almost certainly find that they placed a restriction or charge on the title deeds of your house before the 3 years were up, & I believe they can then use this to go ahead with the sale process at any time. Get your title deeds online from Land Registry to check. If there is nothing there, then they may be out of time but you should query the position with them to be sure.