William Clench had two sons, one of which was presumably the ancestor of our lineage.
John Clench (born between 1475 and 93?)
John under 21, his father Will and his mother Agnes married a Mr "Canbruge when his grandfather Thomas Clench's will was proved 1495. He was in line to inherit:
a tenement in Chalkwell with garden and five acres of land,
eight acres in Nolefield in Borden parish,
one acre and a virgate in Buggisfield,
one acre and a virgate in Schamellisfield,
half acre of woodland in Puc wood ("Putwode" - close to Ospringe, Faversham Hundred).
one acre of woodland at Deneway in Newington parish,
four acres in Bordensdane whereof one acre is in Sittingbourne,
Was this the John Clench who Katherine's will (1503) says "John Clenche be put to school and good guiding by John Berry, John Triplowe" - or this yet a new generation (s/o John or Thomas?)
In Arthur Hessey's will, probated 20 May 1507, he left his "son William a tenement bounding to the lands of the heirs of Clenche" in Chalkwell. This was part of the property being held in trust for John Clenche.
John Clenche was to receive his inheritance at age 21, which could explain the administration of JOHN CLENCHE.15 November 1508. Administration to the goods of John Clenche. To John Triplowe. (A. Act, Vol. 3, fol. 161.)
Note that half an acre of his woodland was in Putwode, Faversham Hundred - If John survived he could be the John Clynch who paid 4 pence in the 14th year of King Henry VIII (James Greenstreet, "Subsidy Roll for the Hundred of Faversham, for Ao 14 Henry VIII," Archaeologica Cantiana, Vol XII, 1878, p. 426).
My cousin John Edwards writes "I'm sure that what the "Administration" entry means is that a John Clenche died in Milton in 1508 ... and the "15 November 1508. Administration to the goods of John Clenche. To John Triplowe." That can only mean that that John Clenche had died without leaving a valid will, and John Triplowe's involvement surely makes it very unlikely that it is a different John Clenche from William's son. Administration was granted (often to a widow) when there was no will or no executor. Looking at the other Milton Wills transcribed by Arthur Hussey in that document, see the two entries for Thomas Bladesmyth on p.84 of the same transcription that has Thomas's and Katherine's wills and John Clenche's administration entry - Bladesmyth's executor John Sethe had died in 1539, hence the need for an Administrator. It's tempting to conclude that John Clenche was still under 21 when he died (presumably in 1508) - or else his estate would have been far more complex than just his goods. This doesn't completely rule him out as our ancestor - of course, he could have had a child (e.g. John) by then; and I wouldn't like to interpret the "when John is 21" line in Thomas's will as to whether (if John died before he was 21, but with heirs) the properties would go to his heirs or to his younger brother Thomas. And as you say elsewhere on the site, that younger Thomas is an alternative possible father for the John who died in 1582.
Thomas Clench (born between 1475 and 1493?)
Thomas Clench was also under 21 in 1495, when his grandfather Thomas left most of lands to John and added:
"If John be dead then to his brother Thomas when 21, but if Thomas dead then be sold, the money :—to a priest to celebrate for our souls £6-13-4d, to the repair of Middelton church £6-13-4d, for painting (picturam) the Images of Blessed Mary and St John Baptist in the church £6-13-4d, Andrew Joye of Ledes my kinsman and his brother Henry Joye each £3-6-8d, the residue in repairing the road between Chalkwell and Middelton, between Bobbing and Middelton, between Chalkwell and Chesten Wood by my Feoffees.
The aforesaid Thomas Clench after the death of Agnes Tunbrigge his mother, have that tenement in Middelton next the Fox which Agnes holds for life, and to the heirs of Thomas for ever. If Thomas die before 21 then to Agnes Brett my daughter and her male issue for ever, in default to heirs female.
Neither Thomas or the tenement in Middelton that he was to have inherited when his grandmother died are mentioned in her will (1508). Katherine left goods for her daughter Agnes, and other provisions for John Clench. Can we assume that Thomas inherited the tenement?
If his brother John died in 1508, Thomas would have inherited the rest of Clench properties.
Thomas would have been in his early 30s by 1523 when John Clynch paid 4 pence in the 14th year of King Henry VIII ((22 April 1523 - 21 April 1524) - James Greenstreet, "Subsidy Roll for the Hundred of Faversham, for Ao 14 Henry VIII," Archaeologica Cantiana, Vol XII, 1878, p. 426. It seems unlikely that this John was his son.
Our Clench lineage descends from a John Clench and Johann who sold their house in Eastling (Faversham Hundred) in the Kent Feet of Fines for 1530/31. Assuming that he was born between 1496 and 1505, John could have been the son of Thomas Clench.