Is your T5.1 left hand drive or Right hand drive? As vw are stating they have had no issues with LHD vehicles.

Check out the thread on the T4forum there are now over 50 T5.1 owners listed all with very low miles and the steering knock/clunk fault.

This is a major fault with the VW T5.1 I purchased a brand new 2013 model, and within 600 miles I could feel the knock through the steering wheel. It is now on 4500 miles and really bad. VW are fobbing us off.

take a look on T5 forum There are more that 40 T5 van owners on the list already. The response from VW is shameful. This is not how a £25k + vehicle should feel. Worth messaging their social media sites/pages facebook twitter etc