I am having this problem! am 11mm Allen key is required, i bought a 12mm and a is just too big. Socket fit allen key is best with a breaker bar and wd40. gonna have a go with new allen key at weekend. 13mm and 15mm spanner too, usual wie brush, screwdriver for leverage and scraping pad guides etc.
Thanks for the reply. You say an 11mm Allen Key, the Bolt looks like the tamper proof splined type? I've been searching round for an 11mm Allen socket anyway, but really struggling to find one up to the job. Does anyone know where to get such a beast, or the part No. for the proper VAG tool. Might halfords hold such a tool?