You want to make the bidding process realy transparent ,use the old saying "money talks and BS walks "
as follows
put in your bid as follows 10% of your offer in the form of an official bank cheque and your offer to expire in 3 days , the geedy estate agents will jump on it, of course if a larger bid comes in you should be able to view the other bidders cheque to see that it is legitimate , as they could see yours .
even if you fail on one proprety when you go back to the estate agent they will know that you mean business and you are not one of the many "tire kickers " out there.
It sends a message that we will not tollerate the pratices that they have been able to get away with for years , the bidders and the estate agents are bound to act in a more professional way