Can't help here.
But this reminds me, sometimes you need to think outside the box. A mate had a fuel pump (Suzuki GSX1400) kark itself on a Tassie trip in 2014. A ring around of Suzi dealers, they were all out of stock, one friendly parts man advised that a Mitsubishi Express (from memory) fuel pump was compatible, plenty of those available, and at less than half the cost.
Not sure if there is anything compatible with the ST1300, could be worth a try though.