Just taken my new-to-me S3 for a check-up at a garage. On my drive home last night, I'd noticed a slight knocking noise from the front, present when I went over larger bumps. The garage have just told me that my front ARB bushes are shot and that I'll need to replace my whole front ARB at a cost of over £400. [Fitted ARB and Bushes = £350 / Full alignment = £90]. Is this right? Are there any alternatives or is it something a competent DIY spanner-wielder can do?