Basic terms of trust law as applied to CGT: separate property
It is quite common, particularly in a will, for there to be one or more clauses that deal with specific property, for example a house or a parcel of unquoted shares. The residue is dealt with in one or more further clauses. This is a strong pointer to there being separate settlements, particularly if there is no possibility of the property falling into residue.
It is also quite common for a will to provide that one half of the residue is to be held on one set of trusts and the other half on other trusts, for instance half the property is held on trust for Mr A for life with remainder to his children and the rest on similar trusts for his sister Mrs B. If there is no direction in the will that the property should be divided into two separate funds, and in particular if it is dealt with as one single block of property, then that is almost certainly a single settlement.
If there are several funds which share some common property, for example land, that is a pointer to a single settlement.