It so happens that almost this entire area, although covering three counties, came under the Diocese of Hereford as far as pre-1858 probate records are concerned and the Episcopal Consistory Court of Hereford in particular.
There is a very useful Family Search wiki article on the Episcopal Consistory Court of Hereford. The wiki very conveniently cross references to Family Search films that can be ordered online and viewed at your local LDS Family History Centre.
The titles of the films indicate fairly clearly what they contain. Here are some I have looked at so far, with some excellent results: see Stary/Sterry Herefordshire Wills.
Original Wills, Administrations, Inventories Court of the Bishop of Hereford 1579-1631 [LDS Film 91671]
Original Wills, Administrations, Inventories Court of the Bishop of Hereford 1602-1623, 1631-1650 [LDS Film 91672]
Probate Indexes and Abtracts, Court of the Bishop of Hereford 1662-1669 [LDS Film 1647469]
Registered Wills, v.17-18, 1709-1714 [LDS Film 91597]
Registered Wills [Court of the Bishop of Hereford] 1709-1714 [Film 91597]
The series 91632-91679 are Wills, Administrations and Inventories 1540+-1660+ proved at the Court of the Bishop of Hereford. Apart from the probate declaration at the end of the document, they are in English and are indexed. They are arranged by letter of surname and year range. However, some of the years are out of sequence. Some are organised by particular surnames.
The series 91588-91621 are complete, registered Wills from 1663-1858 proved at the Court of the Bishop of Hereford. Apart from the probate declaration at the end of the document, they are in English and are indexed. They are arranged by letter of surname and year range. Note however that the index and the Wills they refer to may continue over two films.
The series 1647469-1647653 are only abstracts proved at the Court of the Bishop of Hereford from 1662-1858 and contain only very limited information, such as the most recent parish where the testator lived and the names of the executors.They are also in Latin. However, they are useful as they effectively provide a combined index to Wills and Administrations from 1663-1858.
There are two series that I have not looked at. Films 91680-91716 contain Administrations and Inventories from 1662-1736; films 91622-91628 contain Act Books from 1662-1858.
An Index to Wills proved in the Bishop's Court of Hereford 1442-1579 [Film 990127] is also available.
Apart from the Family Search collection, there are two published indexes for the Court of the Bishop of Hereford that can be referenced at family history libraries and some record offices - if you're lucky enough to have one that is accessible.
Calendar of Probate and Administration Acts, 1407-1550 in the Consistory Court of the Bishops of Hereford, with an Appendix of Abstracts of Registered-Copy Wills 1552-1581, ed. Michael Faraday, 2009
Calendar of probate and administration acts 1407-1541 and abstracts of wills 1541-1581 in the court books of the Bishop of Hereford, ed. M.A. Faraday and E.J.L. Cole, British Record Society, 1989.
But the Wills they refer to in the above indexes evidently no longer exist.
There is a long-standing project by the British Record Society to produce a consolidated index to all records in the Episcopal Consistory Court of Hereford and the Consistory Court of the Dean of Hereford [that covered parishes in Hereford itself and nearby parishes] up to 1700, but this is currently unpublished.
Of course it's one thing to locate a probate record; it's not necessarily an easy task to read it - especially if it's pre-1700 and partly in Latin. But it is possible to teach yourself with enough determination and patience.
And I have found quite a few online resources to help me do this.
But I'll leave that topic for another post!