Ok on my only second purchase of a Bonsai and this one is well developed and
shaped. Must be many years old due to it's main branch structure and
thickness which is especially so at soil level... around 3 inches.

Since my knowledge at present is limited I would like to know how and when
to prune new branches.

As new shoots develop should I consider pruning some of the old branches
too?

It is growing like wild fire in the couple of weeks in my possesion.

I just hate to prune new shoots as I like to see them grow!! However one day
I guess I'll have to take my pruning shears to them :-(

Steve