postcard.co.uk

Postcards of Heversham or Leasgill (both ex-Westmorland ,Now Cumbria) and Caistor (North Lincs)

Unfortunately, I don't happen to have either of those places

You should check eBay by typing those place names into the search box in the postcards section in Collectables. There isn't much activity in here, but you stand a chance on there.