Hi! What's four years between friends?!
I bodged this by doing the following:
Run 'Feature To Point' on your annotation layer - this creates a point at the centre of the text element.
Run the 'Near (Analysis)' tool, with the above output features as in the input, and the features that your leader lines are pointing to as Near Features.
Ensure that 'Location' is ticked in order to get the output co-ordinates.
I had a common field between my annotation layer and the features it was linked to - and added those to the Match Fields section. I haven't tried doing this without this step.
With the output (which is just extra fields on your input layer) - run 'XY Table to Point' using the the NEAR_X and NEAR_Y as the input X and Y Field. This will create your proxy for your annotation anchor point.
Last step should be running the 'Points To Line' tool, to connect your first and second point layer. I used the common field name as the 'Line Field'.
Add and populate the usual CAD fields and you should be good to go.
This method does mean the leader line will always begin at the centre of the anno text - so you lose a bit of 'niceness' in cases where you're after the sticky-outy dog-leg leader style or similar (and also limits you in terms of where your anchor point is located). Certainly beats manually drawing in 1000s of leader lines for me.
