It is not at all clear what name lies behind the spelling Oualet, which occurs once in Domesday Book and nowhere else. In the pre-Conquest personal names of both GDB and LDB, –let most commonly occurs as the end of a name in the spelling –flet for the element –flæd, but the various spellings of –flæd always have an –f– (von Feilitzen 1937: 251) and Oualet does not. The spelling –let also occurs three times for the ON element liðr in the Scandinavian names Winterled and Sumerled, but there is no Old Norse element which could conceivably have been written Oua– even allowing for gross miscopying. Final –let also occurs in two eccentric spellings of the Continental name Vitalis (Phitelet and Vithelet), where it has been regarded as the Romance diminutive –et (von Feilitzen 1937: 405–6), but that is no help either.
It is also very unlikely that the name ends with the rare OE diminutive suffix –ede, which in all the examples that have been noticed has both a –d– (not a –t–) and a final –e (Redin 1919: 161–2; von Feilitzen 1937: 322 and note 3).
More promising is the possibility that –let is a miscopying of –iet, a common spelling of the common element –geat. That still leaves Oua– impossible to resolve without supposing bad miscopying. The best guess might be that the underlying name was Wulfgeat, since that name was occasionally spelled in DB with an initial O– and even with an initial Ou–, Ouiet being found on four occasions (von Feilitzen 1937: 419–20).
Redin 1919: Mats Redin, Studies on Uncompounded Personal Names in Old English, Inaugural Dissertation (Uppsala University, 1919)
von Feilitzen 1937: Olof von Feilitzen, The Pre-Conquest Personal Names of Domesday Book, Nomina Germanica 3 (Uppsala: Almqvist and Wiksells, 1937)
Spellings in Domesday Book: Oualet
Forms in modern scholarship:
von Feilitzen head forms: Oualet
Phillimore edition: Oualet
Alecto edition: Oualet