That's going to be a long time.

Look at northern inland there are places in Ireland and parts of Scotland and even the USA where I would have to be careful as I am a product of a mixed marriage and I also was a a "crown servant for 15 years" and have a southern ie catholic last Name.

Parts of the UK that have so much immigration from India that the local population are majority desi are few and far between. There’s nothing like historical Irish immigration to Britain. Scottish Catholics before 1970 or so were all descendants of the Irish and that’s what ~40% of the Scots? There were so many Irish in Liverpool they elected Irish Parliamentary Party MPs before the Irish Civil War. And still assimilation proceeds rapidly. Wayne Rooney Player for England, not Ireland. Out marriage is the death of ethnic identity. Look at the US. There are actually people identify as White, or as Asian American. How far does a Chinese, Vietnamese or Japanese person have to be divorced from their culture to think the most important thing about their ethnic identity is their skin color? Similar dynamic earlier in US history when the ethnic marriage markets collapsed into religion bounded marriage markets, when Herberger wrote Catholic Protestant Jew. Once people are willing to marry out assimilation is a matter of time absent continued immigration. Irish immigration to the US dropped off a cliff in the 1990s. One day South Boston will be known for some other group, not the Irish, just like Little Italy turns into Chinatown.