Steering wobble

My 2001 1.8 Petrol has recently picked up a wobble through the steering. I originally thought this might have been simply wheel balancing but now, combined with a slight noise on turning, I'm thinking it's more likely to be a wheel bearing.

Can anyone help with the following:

1) What's a 'normal' interval for chaning WBs on a Freelander (mine's done 78k and it's highly likely they've never been changed)?
2) How complex is the job of changing (bearing (sorry) in mind that I've changed 10s of bearings on MGs and Minis so am at least partially aware of the job's pitfalls/issues)?
3) Does anyone market a complete kit - if needed - or is the bearing itself all that's normally required?

Of course, if anyone can suggest any other possible causes I'd be interested? Haven't had it up in the air yet since it's always p**sing with rain, snow or frost at the moment.

Jon

My Hippo is at 90K and is still okay, bearing wise. I had a drive shaft replace recently and asked the mechanic if it was worth changing the wheel bearings while the hub was apart. He commented that it was two hours work on top of what was already being dismantled. I suspect there is a lot of messing with pullers and presses involved.

Could be bottom ball joint....more likely to cause wobble than a bearing....normally notice noise from bearing well before wobble and if it is bearing and wobbling will need changing sooner rather than later