"… but now that big Hufflepuff player’s got the Quaffle from her, I can’t remember his name, it’s something like Bibble – no, Buggins –"
-- Luna Lovegood (HBP19)
Cadwallader is an English rendering of the Welsh name Cadwaladr, which is derived from Ancient Welsh cad "a battle", plus gwaladr "leader". The badge of Cadwaladr ap Gruffudd, a king of Gwynedd during the 7th Century, is the red dragon now on the Welsh flag (Behind the Name, Wikipedia).
This surname is shared by Eurig Cadwallader, who played Seeker for the Welsh National Team at the 2014 Quidditch World Cup tournament (Pm). It is possible that this is the same individual or a member of his family. -BB
Lexicon list of Chasers
From the Web
Harry Potter Wiki: Cadwallader