Hi Physiobob,
As you seem to know about climbing I'll say a little more...
When I start climbing again in November, my plan is to start with the basics again, traverses around the bouldering area and easier slab climbs on top rope. If this feels OK, then would look to shorter vertical top rope routes and again if nothing hurts give easier vertical indoor lead climbing routes a go. If something starts to pull or strain then I plan to end the session. I dislike falling and try to avoid it!

I feel, maybe incorrectly, that my surgeon does not fully appreciate the 'unique' forces at work on your shoulders when climbing. I am keen to progress sensibly at the wall and get myself into as good a shape as possible prior to getting to the wall.