Good point about the will in the UK v the will in the IoM, although that is if he was free to marry Caroline.....
With the Crook family in the UK, I can see him on the 1881 census shows him as married to Alice (aged 46), living in Wigan, Lancashire. They had 3 of their own children together and Alice had been widowed previously and had so he had 2 stepchildren.
He is the then on the 1891 IoM census, after marrying Caroline, which he is shown as "widowed" on marriage certificate
Looking at the children that John Crook had with Alice, Alice appears on a 1911 census (aged 77), widowed and living with one of her daughters (not a daughter of John Crook), Wigan
Whether this Alice on the 1911 is the wife he married before Caroline, perhaps this is why they had an issue with the will
How would I order/obtain a copy of the IoM wills? Am I able to do this online?