who can answer me this

I am just wondering what those with experience with takeover bids can tell me on these queries.

Qu: 1.a) Do you feel that TPG and Global will have to walk away because they cant get in and do their due diligence ?
b)If not, do you think this bid is an attempt to flush out a serious bidder to the table?

2. Legally speaking if they wont bid any higher, can they come back at a later date and make another offer or do they have to stay at the negotiating table to be a contender in any governing body's eye eg ASIC ?