(1) The grandparents of an intestate are entitled to the whole of an intestate estate if the intestate leaves--(a) no spouse, and(b) no issue, and(c) no parent, and(d) no brother or sister, or issue of a deceased brother or sister.
(2) If there is only one surviving grandparent, the entitlement vests in the grandparent and, if 2 or more survive, it vests in them in equal shares.