Can't remember if this was asked before but does the 1933 marriage certificate list an address for Sadie?
Address given for both Bride and Groom as 'Cross Street Larne' (no number) - as Sadie's occupation was 'Shop assistant' I assumed she may have lived 'over the shop'. Today there is an Upper and Lower Cross Street shown on Google maps which consists of a lot of shop premises along its length.
Another assumption is that the witnesses Daniel McAuley and Agnes Fleck were from the family that owned the shop.
This is of course just speculation on my part.