Any idea what could cause this?
Hi Ozzy just seen your post and it sounds weird what you are describing but definitely not road worthy .
Best thing to do is either Jack up the front end and put it on axle stands and check for any play from all suspension components and also gearbox and engine mounts and supports .
If your not confident in doing this or have no private space to do this , then take it to local garage where they have a ramp and , explain to them what's happening and they can check it over for you and hopefully find the
problem a nice drink should keep them happy and also you might find that its something they could sort out not too expensive.
Hope this helps.