Previously, I believed that the parents of 1050811Joan ___ were 2101622Thomas de Dene and 2101623Martha de Shelving. However, researcher Pete Andrews called my attention to 2101622Thomas' inquisitions post mortem, which I had overlooked. 2101622Thomas' two IPM's strongly suggest that he is not 1050811Joan's father (since the IPM explicitly notes 2101622Thomas' daughter Joan as deceased in early childhood, among other incongruences).

Nevertheless, because 1050811Joan certainly seems to be related to 2101622Thomas in some manner, and because my older work could prove useful for future research, I've isolated the profile pages that I'd written for 1050811Joan's formerly proposed ancestors into a separate section of my website, starting from the old version of Joan's page onward.

You can see a list of those ancestors or a family tree of them.
33625961Isabela de Gatton
Key Facts
Parents:67251922Hamo de Gatton
67251923Mabel de Gatton
Born:by June 1216
location unknown
Died:unknown
Buried:unknown

As explained below, 33625961Isabela de Gatton's parents are 67251922Hamo de Gatton and 67251923Mabel de Gatton, and 33625961Isabela must have been born sometime before June 1216.

Problem: Resolved
Who is 33625961Isabela's mother?

In Henry Elliot Malden's The Victoria History of the County of Surrey, volume III, page 32, footnote 85, we read:

Assize R. 80, m. 3 d. Robert de Manekesey married Mabel's daughter Isabel

As best I can tell, this refers to JUST 1/80, m. 3d, which you can see at these two URL's:

http://aalt.law.uh.edu/AALT4/JUST1/JUST1no80/bJUST1no80dorses/IMG_0305.htm
http://aalt.law.uh.edu/AALT4/JUST1/JUST1no80/bJUST1no80dorses/IMG_0306.htm
For reference, you can see 3f here:
http://aalt.law.uh.edu/AALT4/JUST1/JUST1no80/aJUST1no80fronts/IMG_0257.htm

I was unable to find the entry that Malden cites, but the text is admittedly difficult to read.

Similarly, in Archaeologia Cantiana, volume V, page 222 insert we see:

Quo War. Roll, Surr. 25 H. III rot. 1 dors. [...] [33625960Robert de Mankesey] held [property at Cateshull and Ertindon], 1241, as given to him "in maritagium cum Isabella filia eorum."

I think (but am not sure) this refers to JUST 1/867, m. 1d, which you can see at these two URL's:

http://aalt.law.uh.edu/AALT4/JUST1/JUST1no867/bJUST1no867dorses/IMG_8866.htm
http://aalt.law.uh.edu/AALT4/JUST1/JUST1no867/bJUST1no867dorses/IMG_8867.htm
For reference, you can see 1f here:
http://aalt.law.uh.edu/AALT4/JUST1/JUST1no867/aJUST1no867fronts/IMG_8820.htm

Again, I was unable to find the entry in question, but the text is exceedingly difficult to read.

Despite my inability to find the original sources cited, both the Victoria History series and Archaeologia Cantiana are generally very reliable, so I'm confident that the evidence exists (somewhere...) and that 33625961Isabel's mother is indeed 67251923Mabel.

Problem: Resolved
Who is 33625961Isabela's father?

A pedigree in Archaeologia Cantiana (volume V, page 222 insert) asserts that 33625961Isabela's father is 67251922Hamo de Gatton, who (according to the pedigree) died by 4 June 1216, probably in 1214.

At first glance, one could have reasonable doubt about this claim. I have seen no document that explicitly states that 67251922Hamo and 67251923Mabel were even married. Even if you accept that they were married, the dates involved with 67251923Mabel's marriage, widowhood, and subsequent re-marriage leave open the possibility that 67251923Mabel's second husband Thomas de Bavelinham could have been 33625961Isabela's father rather than 67251922Hamo de Gatton: As stated in the pedigree, we know that 67251923Mabel seems to have been unmarried as of June 12161 (Charters apparently from the same period explicitly describe 67251923Mabel as widowed.2), but she had (re-)married by 26 January 1218/9.3 Her daughter 33625961Isabela seems to have married by November 1234.4 Hypothetically, 67251923Mabel could have married her second husband Thomas de Bavelinham circa 1217, conceived 33625961Isabela with him, and 33625961Isabela could have been ~17 years old by the time she married circa 1234. Judging merely from the dates involved, it's plausible that 33625961Isabela's father could be Thomas de Bavelinham.

Fortunately, though, 33625961Isabela named her son 16812980Hamo de Gatton, who likewise named his son 8406490Hamo de Gatton, too, as is proven elsewhere on this website. The name repetition gives weight to the hypothesis that 33625961Isabela's father is 67251922Hamo, not Thomas.

As alluded above, 33625961Isabela had married 33625960Robert de Mankesey by November 1234.4

Sources Cited:

1: Thomas Duffus Hardy, ed., Rotuli Litterarum Clausarum in Turri Londinensi, Volume I (1833), page 274, left column, near the bottom.

2: Archaeologia Cantiana, Volume V (London, 1863), page 210 et seq.

3: UK National Archives reference C 60/11, membrane 9, an entry dated 26 January concerning Thomas de Balinghem et al. Thanks to the Henry III Fine Rolls Project, you can see the "original" copy at <https://finerollshenry3.org.uk/content/fimages/C60_11/m09.html>. The Project's translation of this entry reads, "26 Jan. Westminster. This fine is enrolled in the Fine Rolls of the time of King John. Order to the sheriff of Surrey that since Thomas de Balinghem and his wife, Mabel, Adam de Bendenges and his wife, Alice, Roger of Leybourne and his wife, Eleanor, Ralph son of Bernard and his wife, Eleanor, and Ralph de Fay and his wife, Beatrice, made fine with King John, father of King Henry, for five palfreys, for having all land formerly of Stephen of Thornham which falls to Mabel, Alice, Eleanor, Eleanor, and Beatrice by hereditary right, and having accepted security from Thomas and Mabel, Adam and Alice, Roger and Eleanor, Ralph and Eleanor, and Roger and Beatrice for rendering the five palfreys to the king, he is to cause them to have full seisin of all land formerly of Stephen with all of its appurtenances in Artington. Witness the earl."

4: Calendar of the Charter Rolls [...]: Volume 1, Henry III, A.D. 1226-1257 (London, 1903), page 188.