Not necessarily, i think it depends largely on how soon you catch the problem
Its not the bearings being shot thats the problem, its the effect of them being buggered that is.
If the bearing dies, commonly through lack of lubrication (which can be caused by a knackered seal behind the ARB plate- water leak washes away the grease) then without the lubrication the bearing will grind away on your axle pins (where the trailing arm slides onto)
This is a pic of what one of the pins will look like if the bearing has 'chewed' away your pins
So if you havn't diagnosed the problem soon enough then no matter how many bearings you change theyll soon get destroyed again due to the uneven rough surface that is now evident on the pins.
They should look like this...
So if they have gotten to the bad stage then you have 3 options:
1. Buy a new axle for £370 and gradually build it up with new bearings etc- costly but you know itll be spot on after
2. Replace with a 2nd hand beam, check this for any wobble first if you can aswel. With this kind of thing though you really dont know what you're getting.
3. As mentioned before jpsaxo and his dad refurb axle's in their spare time.
The above pin in the pic is one specially made as a replacement- citroen dont make these as seperate parts which is why you have to pay for the whole lot.
As they get the pins made up the old ones are removed and the new ones pressed in.
Send him a PM about prices