Ah T-2 d.o.o. (whoever they are may have given the game away)...... when we swapped hosts we had a chap based in Slovenia who was helping up us to migrate our websites.
We assume this must have been a staging domain he may has used and explains now why we are getting this email.
So the provision that wpmojster.de. or shedmaster.wpmojster.de is NOT our domain that this is something we don't need to worry about.