In Scotland it's known as 'obtaining confirmation of the estate'. How long it takes? It depends on whether it's a small estate (less than �30K) or a large estate (more than �30K). A small estate can usually be dealt with without a solicitor.
As I undersand it, the guidance is that the executor has to wait at least six months before they can begin to consider settling the estate. It's to make sure all creditors are identified before the estate is distributed. Remember that inheritance tax may be involved so nine months to a year may be more realistic.