Is "havening" pseudo-scientific or effective?
First off, I am not familiar with this therapy. There seems to be 251 hits on Scholar (excluding citations and patents) at the time of this writing with a search for "Havening Technique'. Of these 251, there seems to be one single journal article from Gursimran et al. (2015). The publisher of this 'journal', i.e. the Health Science Journal (Insight Medical Publishing) is listed on Baell's list and hence a suspected predatory publisher. 

In all, this Havening technique can safely be considered as a technique that has not been described in the scientific literature. 

I am deliberately leaving out the reference to the paper, as I regard it a source, not a reference