Pruning a magnolia
I have an excellent magnolia (in England), 30 years old, a near perfect cone 25 feet high and similar diameter. But it has outgrown it's site. I want to reduce it by 5 or 6 feet all round and from the top as well. But I'm worried the shock will kill it or it'll grow masses of water shoots. Any suggestions on how I can achieve the pruning without ruining it?