Never fitted one, but looking at a photo of the complete lever on eBay, it doesn't look like anything underneath holding it in.
So as you say cables off (by the way noted wear /rust around the metal ball joint connected to the arm on the lever) then disconnect the spring on left side, on the eBay one it looks like a "spire nut" type clip to release , but not sure .
It then looks like a case of levering it up and out of the plastic cup, it may help if the cup stays behind until able to squeeze the plastic crown ears inwards to release it.
I recently changed the gear cables on a 2010 Doblo Maxi 1.6 multijet and found it easier to pry the sockets off the ball joints by placing an open ended 13 mm spanner between the two parts to ease it off.
Looking at your old one , you may need some silicon grease to help assembly.
Perhaps another Forum Member has changed one recently to give current advice?