Mike:
I have not yet been able to locate my Yorkton contact information. It was some years ago, so I'm not sure I will be able to locate it. My father joined the 2nd LAA on March 3, 1943, so he may have been at Eastbourne. The next movement in his record is embarkation for Sicily in June.
I did however dig up the following Dept of Defense report which has some mention of Eastbourne and the 2nd LAA. Check out page 21 and the tables at the end. The document discusses the formation and role of Canadian units in the defense of the UK.
http://www.dnd.ca/hr/dhh/Downloads/cmhq/cmhq106.pdf
Hope this helps.
Murray