Could not find the place where Ivor claims to be a thousand years old.
We don't see him say it himself, when Brone recounts how he was turned Eleanora says 'Some vampires, like Ivor, are a thousand years old- or older-', of which one possible interpretation is that he has claimed such an age to her in the past. The other would be that she is exaggerating to Brone herself.
Also around this point Brone says he had never seen a naked woman before, but in his bad end he says that he had not been with a woman since the 1820s. Given that we never hear of him marrying and that he's a devout Catholic, it wouldn't surprise me for him to have never done so.
Did not change anything regarding Brone's story, as seen in The Anax: Call of the Cursed One, he joins Anax at Ravenhurst Manor sometime between 1845 and 1854, so this all remains accurate.
This definitely makes Ellis Island seem like an anachronism then if he was already at Ravenhurst Manor by 1854. The processing of immigrants there wasn't until the 1890s.
Also, did Portland have any real dockland before that period either? The Port of Portland was established in 1891, that would have made Brone quite old if he met Ivor after that.
Plus the part that says Eleanora 'caused such calamity a century ago, costing your employer and friend, Anaximanes, his very life!' would seem to be understating how long ago it was by quite a bit.
And Brone says he has 'lived' in the Portland tunnels for 'almost' a century, though that may have been much later than when he was turned.