Pendry could equally well be a Cornish name. The old rhyme "Tre Pol and Pen spell the names of Cornish men" has some truth to it. I am connected to the Pendrys of Berkshire, who date back at least as far as the 1730's with no sign of roots in either Wales or Cornwall! There are clusters of Pendrys in Wales, Cornwall, Herefordshire, and Berkshire/Buckinghamshire as far back as the C17th. To confuse the issue still further, I know at least one branch of my family that moved to Monmouth FROM the London area in the 1800s!
Spellings of Pendry prior to the mid 1800s vary enormously and tend to be phonetic. Even my gg-grandparents signed their Marriage Certificate with an X. This is because very few ordinary folk were literate and it was up to the person filling in the parish registers to decided how to spell it based purely on what they heard. What they heard also depended upon the local accent.
I have seen Pendry, Pendery, Pendrey, Pendray, Pendrie, Pendree, Pendrigh, Pandry, Pindrie, etc. etc.!