They wouldn’t have changed their name though. There has been Somalis going to Wales and Sheffield around that time period. In fact the oldest SomAli community is found in those places i mentioned and no, there is no record of any of them changing their name to an cadaan one.
There is nothing unusual about a Somali living abroad in the early 1900s. Many Somali men were sailors who would often have to live in the UK and other places. We have records of Somali in Yemen in the 1880s working for British ships.
Many immigrants changed their first and last names in North America at the time though to something more Anglicized either through spelling or the whole name entirely. Its not farfetched that a Somali had to do it who would stand out way more. I see it all the time today of people who are multigenerational Canadian but not from Britain with obvious Anglicized names. If you look up famous non-British descent people, you'll find many cases of this. An obvious example is Trump's family. There was a lot of discrimination against non-WASPS then or those not culturally Anglophone. You had to integrate as much as possible back then.
Those Somalis obviously married gaalo. There were no Somali women there then.