Seems the problem of finding a reliable builder for cathedral improvements was as big a problem then as it is finding a decent builder these days. Bodgit and Scarper Ltd were clearly well established in Tudor times.
There are a couple of older tombs just to the right of SWMBO in the picture, and they decided they wanted to build a big tall impressive tomb/chapel/whatever on top, for Prince Arthur. The filigree masonry and everything is just staggering. But when they came to assemble all that fancy carved masonry screen, they found it was about six inches too high.
So rather than go back and do it properly, they just hacked away at the existing fabric of the cathedral, and hoped no one would notice.
Nearby is a carving of a spit-roasted human… one of the masons perhaps.