Addendum: Virtually Free pro-$p$ groups whose Torsion Elements have   finite Centralizer
  We fill details in the proof of Lemma 13 in Bull.London.Math.Soc 40 (2008) (that is Lemma 3.2 in arXiv:0712.4244v1). 
Wolfgang Herfort and Pavel A. Zalesskii
math.GR