Reg hall was collecting superb Irish music in London before the revival started in the early 1950s and continued to do so to the end of the century

It might be a good point here to mention Reg Hall's encyclopedic study of Irish Music in London, A Few Tunes of Good Music which, amazingly, is available as a free download for all forms of e-reader. It can be downloaded by clicking here.
It is a mighty and hugeelu important read written after decades to total involvement and detailed research on The London Irish music scene - compulsory reading in my opinion.