I had very similar symptoms (right arm and right side of face though, not leg), in three separate ~10min episodes over three days last year Numbness in those areas and pins and needles, but no brain fog/neurological impairment/pain. Went to the hospital after the third episode and it turns out it was a brain bleed/chronic subdural hematoma caused by a bike accident two months previous where I suffered a bad concussion, that was pushing on my brain and creating the symptoms, though they initially suspected a TIA. Had an operation to remove the clot with has fortunately left basically no lasting effects.
Get yourself to A&E asap, as said above, particularly as you mention a bad crash at BPW. Better safe than sorry, hope it turns out to be nothing to worry about!