Updated scrapers to post to new check_exists URL for materials.
Updated scrapers to post to new check_exists URL for materials.

ElixirUK/newtessscraper,ElixirUK/newtessscraper,ElixirUK/newtessscraper,ElixirUK/TeSS_scrapers,ElixirUK/TeSS_scrapers,ElixirUK/TeSS_scrapers