Yes that's very true indeed

it's all too easy to get carried away and want to fit the info to an emerging narrative. Thank you SO much for your help so far. I'm afraid I haven't been able to crack the Dutch documents yet.. but maybe other records from the wider family will bring more certainty to the inner muddy bit

Having said that, on another issue of doubles...
So it turns out that (thank you again for the clipping ciderdrinker) JC Lyons who married Miss Cohen (Judah's daughter) in 1832 was a Joseph Lyons, his wife was Esther Cohen born in 1813 according to census info. Joseph was born in Portsmouth and they had children in Manchester, Liverpool, Hull.
7 children: Theresa 1834, Julius 1838, Elizabeth 1841, Fanny 1842, Laura 1844, Victoria 1846 and Rebecca 1849.
But I suppose there's a problem then in that Esther Cohen born in 1813 would be (if correct) the daughter of 'my' Judah Cohen and Esther which would be unusual as in Jewish tradition a child wouldn't normally be named after a living relative. Esther Lyons was back in London by the 1881 census as a widow, with 2 of her daughters Theresa and Victoria and a grandson.