I am reporting evidence I have found on behalf of a descendant that the Crockers of Lanihorne in Cornwall are likely direct descendants of the Lyneham Crockers
The Crockers came late to Cornwall. At the 1569 muster there were only two families of Crocker: William/Richard of the Morwenstow area, and James of Lanihorne. At that time the Crockers/Crokers/Crochards had been thoroughly established in Devon for centuries.
However, we know that Elizabeth Pollard, 2nd wife of John Croker of Lyneham (who died 1523), remarried Sir Hugh Trevanion in Caerhays Cornwall, giving the Crockers a possible introduction to the area or even a claim.
Between 1587 and 1621 we have an Edward Crocker acting as agent for Lord Edgcumbe in Caerhays, doing land transactions (odd as he was illiterate). From his 1621 will, it is clear that Edward is the 6th son of John Crocker jr and Elizabeth Strode (see Visitations of Devon and (http://members.iimetro.com.au/~rosewarne/probate1.PDF or the Lanihorne OPC site.). His brother Thomas also is around and has issue – he jointly signed a 1587 document in Gorran and is mentioned in the will.
Now the modern Crockers of the waterland area between Tregony and Veryanare all descended from brothersPascow and Parkin Crocker of Lanihorne (which adjoins Caerhays). In 1620 and 1631, Pascow (gent) is involved in land transactions with Richard Trevanion of Lanihorne. This seems too much of a coincidence to me given the past Crocker/Trevanion connection.
I therefore consider that Pascow and Parkin are either sons of Thomas Crocker 8th son of Lyneham (and therefore grandsons of Elizabeth Trevanion/Crocker) or are sons of James Crocker from the Muster. In the latter case there is also a fair chance they are descended from Lyneham. These are the only possibilities.
All this evidence is indirect – but as good as you will get prior to parish records which don’t begin in the area till the 1670s . There may be wills we haven’t seen – and there is always Y-DNA if we can find another Crocker descendant of Lyneham (the main male line is extinct).