Hi Mike
You have raised the thread in case newby's like me haven't seen it. What you have also done is raised awareness of obstacles which is also very good. As newbies we are probably to busy finding out how to do it and what with we probably would thing of many of the obstacles until we are confronted by them. Hopefully your message will encourage others to share how they have round fencing or fencing posts, close to buildings etc. My thoughts for trees, shrubs and fencing is put them in after the grass but there are bound to be times, particularly if we change things, that we will come across items that are in the way.