It's not the only graffiti there (it has a lot), but it caught my eye.
The first line looks as if it was carved by someone who didn't have an extensive knowledge of writing, except for the ES (I think that's what it is) to the right. The second line looks to be a date, 1151, but that seems unlikely given that there was a fire in 1188 that destroyed much of the building, and the over-optimistic reconstruction collapsed in 1219. It could be connected to the letters above it, which if you use your imagination could then read "William".
It was the final line that I was interested in, though. 1642 marks the beginning of the English Civil War, and King Charles I stayed at Beverley for three weeks in April that year having been denied entrance to Kingston upon Hull. It could be that the 1642 is attached to the ES above it, or to the FFGL to its left. I don't know what either of these mean; I'd guess that the ES is a person and the FFGL is an acronym for something in Latin, but I haven't been able to find out more.
This kind of permanent graffiti seems to have a different content to the more temporary, spray-can graffiti that we see these days. It's more documentary than art movie.
I'm sure the Minster authorities will get around to repairing the damage eventually, anyway.