Exactly. This is one of the best copyright disputes I've seen in years.
The goal isn't copyright enforcement at all because noone (up to and including David Slater's own lawyers) is sure who does own the copyright.
Rather, it appears to be an attempt at preserving David Slater's revenue stream by paying lawyers to rattle a few sabers.
Going outside the terms of a retainer is classed as professional misconduct where I'm from. A lawyer should not take any action on your behalf without, at the very least, implicit instructions to do so.