as above can it be done by changing centres ornot cheers

nope...
ea is bw75 series with 25 spline axles and au is bw78 series with 28 spline axles..

the centers will fit but u have to change the axles as well .. im running a EB xr8 sedan lsd center and axles in my auII ute atm with no problems

in your case the ebxr8 had a 28 spline axle and so does au, the eb centre can be fitted and the au axles used..you couldnt have used eb axles in your au, they are 2 short..

the problem is ea has 25 spline axles, where the au is 28 spline, no au's have 25 spline axles.
and the au diff being about 70mm longer means you wont find 25spline axles that long unless he gets billet axles made up...
which kind of defeats the purpose of doing it on the cheap...