Whenever I needed an OEM part for my Ninja I would go to FortNine because they sell Kawi and Suzuki parts. I'm having some difficulty finding a Canadian parts distributor for Triumph, though.
The part in question is silly - the rubber pad that sits between the frame and tank. Part #T2400643. Here it is on Triumph EStore https://www.triumphestore.com/p/Rubb.../T2400643.html for only $2.06 USD... add to cart, slapped with a $45 shipping fee.