Rightmove, Findaproperty, Primelocation and PropertyFinder have the vast majority of market share of users based on years of brand building and marketing including search.
Globrix has a small market share of users which is achieved from from the free marketing they get from the Times which can't continue indefinitely (it's not really free if someone else is prepared to pay for it).
Their advertising revenue model hasn't been proved yet so they are not safe. They might be gaining market share but it's not to difficult to carve out a small share. Findaproperty, PropertyFinder and Primelocation have all taken years to claw their market shares from Rightmove including the use of very expensive TV advertising.
Property Live will probably be more successful than Globrix as the agents will promote it themselves and they can be sure that it won't threaten their business model. If Globrix ever becomes the market leader, they can start taking private listings which really would be the end of the agents.