as said above hi-q arent the greatest, i used to work for them and they tend not to get involved in much more than tyres and exhausts as its easier money and they dont know a huge amount about much else,
although this couldjust be the store i worked in,
if any thing decent came in and i tried to look at it i got a bollocking saying tos too much hassle and not to get involved.

sounds like the lower arms to me, but get it to a garage for them to properly diagnose the problem