I found that report in the local newspapers available through the Imuseum. I hope to be going again soon - maybe next week - so will have a look for any more info if you like.

From the article in the paper it seems the Douglas Bay Swim was quite a regular event, it mentions a previous attempt three weeks prior to the report and a further attempt the Tuesday following the Sunday event.

It would be good to find out more about it - I'm looking for R Hannay and R Kewley and T Kewley who all completed the swim but I haven't found the reports yet. Will let you know what I find.