Mags L Halliday has reviewed the accessibility of the parties' local manifestos, and has kindly allowed me to post a summary her findings here. (For completeness, I've storified the relevant tweets below.)
In ascending order of scores, the results are...
... drumroll ...
In joint last place, Exeter Conservatives, with a score of -1, for an unreadable PDF that returned an error about font sizes and refused to load an image. [It was fine for me, incidentally; but failing to open for some people clearly means it's not very accessible!]. Mags also notes that the document is "a print PDF hosted online, as the colours, fonts etc are not accessible for the visually impaired".
Also in last place, Exeter LibDems, for lacking local pledges. Their website is "at least fully accessible, but the last local news update was Feb 2011". [There's also a problem with the South West manifesto hosted on the national website, in that it's actually for the North West...]
UKIP also scores -1 for lacking a manifesto specific to Exeter.
In second place, with 0 points, Exeter Labour. It gets 1 point for its manifesto being html rather than PDF, but minus 1 point "for a gray font on a gray background... and the font is also serif and in italics".
And in first place, with an unassailable 1 point, Exeter Greens: "only @exetergreens have local pledges up and easily read by people with disabilities, but they don't have a biog of my candidate"
P.S. Mags warns that she wasn't able to check accessibility with a screen reader. I've sent the links to a blind friend, who has just replied to say that they found the Greens' pdf to be unreadable. So I don't think any of the parties come out of this well!