The difficulty is that it interferes with 15a, which I have seen in Another Place as CINERAMA ( Manic flicks capturing historic time in Hollywood technology )
GG....yes, it does ....looks like an American spelling, although why a British newspaper should use American spellings, rather than the correct English ones is beyond me !
Looks like an error to me. Swift clearly spelt the name 'Brobdingnag' and while Chambers 2016 doesn't list 'brobdignagian' at all, OED clearly shows it as 'Erroneous' rather than as any sort of valid variant.