One word of warning here.
I had a set of H+R lowering spring fitted to my van about 4 years ago. Last year just before we were about to go away I needed to get some clanks coming from the suspension sorted.
As time was short the only booking I could get was at my local HWCV dealer. However, they would not look at the van because the suspension was 'non standard'. With the help of the Service Manager I got round the problem and made the ferry, but not before replacing the H+R springs for a set of VW Ebach lowering springs, which were in stock, and new anti-roll bar drop arms, which were seized causing the noise.
The edict from VWUK is that VW dealers are not allowed to work on anything that is not standard VW supplied kit. For Health and Safety reasons according the sympathetic Service Manager.
Alan