The 'fast walking pace' taxi theory is outdated, and general guidance is to taxi at a reasonable speed, and to '...consider the safe and expeditious movement of traffic' (CASA Flight Instructor's Manual).
expeditious (adj) - characterised by or done with speed and efficiency; prompt; quick.
VH-XXX - if you're not doing anything dangerous, then the old whinger's really got nothing valid to whinge about.
Normal taxi speed for larger aircraft is about 20 knots.