Worth noting that the Scottish National Party (SNP) is broadly pro-immigration:

"The SNP believe that immigration is essential to the strength of our economy and adds greatly to our cultural fabric."

https://www.snp.org/pb_what_is_the_snp_s_policy_on_immigrati...

The SNP is sometimes described as being about civic nationalism rather than ethnic nationalism:

https://en.wikipedia.org/wiki/Civic_nationalism

Edit: Arguably the closest we've got to ethnic cleansing was the Highland Clearances - which were inflicted on Gaels by landowners.