"The bid is expected to be made subject to a number of...

"The bid is expected to be made subject to a number of conditions including regulatory approvals, a 90 per cent minimum acceptance level and Spotless hitting its earnings guidance. "
http://www.copyright link/street-talk/ubs-raiding-spotless-group-for-downer-20170320-gv285c

They must expect the process to take a while, if its conditional on the full year results, and regulatory approval.

Hard to predict regulatory approval, but i wouldnt think there would be a problem, Downer is an Australian Company, and there probably isnt much increase in concentration of services.