XC60 Intermittent vibration when driving

[Emrys17]

Hi, We've noticed an intermittent issue with our 2011 XC60 D5 AWD whilst driving. Most of the time it doesn't happen at all on a journey and we can go weeks without it occurring at all, but sometimes particularly on a longer journey or if braking or accelerating hard from standstill or going uphill it appears.

The steering wheel starts to shake, gradually getting worse and worse until the whole car is shuddering. Braking also judders when the issue occurs. Slowing down doesn't seem to help but stopping completely at a junction or pulling over and pulling away gradually often sorts it out again in most cases but can re-occur again in a journey especially when following behind a nervous driver who keeps panic braking constantly. I have found that sometimes blipping the throttle and changing up and down the gears can sort the issue out after a few miles too and the car will drive fine for a while. I could come back to the car the next day and drive it for a few weeks without issue.

The car has been to have the wheels rebalanced recently but whenever I have experienced issues with wheel balancing, it has been a fairly consistent issue with shaking and not intermittent.

I have checked that the wheel nuts are all tight and a visual inspection of the tyres for any damage but wondered if anyone else had experienced the same issue at all and what the likely cause might be?

Thanks