I have come across a card back with an earlier first use date of 11/09/1907.
An Ebay card shows a first use date of 22/08/1906. The link is: Redcar Coatham Road 1906 Postmark Tucks Glosso 5560 | eBay
@PhilW thanks again for that updated information and link to ebay. I grabbed the back and updated the first use:
https://tuckdbpostcards.org/items/142073