See allthegearbutnaeideas reply!
IMO your TR should be played as soon as possible where you have a strong chance of at least getting 6 points from it! That should have been in Heat 7!
He put Wells TR in heat 10 (against the unbeaten pairing of Morris and Holder) but I still personally would not have done that despite his reason of gate positions! Harris had a bucket load of speed in that bike and was more than capable of not running a last place