PDFx won't see links in some PDFs

PDFx won't see most of the links in the PDF below. Is this a known issue? Is there a fix for it?
Many thanks!
https://webarchive.nationalarchives.gov.uk/20160613090753/https://www.litvinenkoinquiry.org/files/Litvinenko-Inquiry-Report-web-version.pdf

[htInEdin]

There are actually several problems with link processing in pdfx and pdfminer. I'm working on a pull request to address as many of them as I can, but in the interim the attached
simple patch (against pdfx version 1.3.0) will fix the most serious one.

This patch increases the number of links recovered from the above linked file by harvesting Link annotations (as opposed to those scraped from the text) from 3 to 1067.

backends_patch.txt