Few if any would actually taxi at walking pace. That would make this particular taxi venture take several minutes to complete. So even though it probably felt slow it would have been more like a fast walk/jog. EN Twr are a great bunch of blokes/gals they always get the slow coaches to move along or move aside for us bigger thirstier beasts:-) A normally slowish taxi speed for me is around 10+kts (18+k's) (as per the little God send contraption GPS) & I often find it feels like I'm crawling! So walking speed is borderline stopped!
Taxi to suit the conditions but like the road bear in mind that even though planes don't have rear view mirrors there could be someone else behind getting frustrated if yr crawling.
Wmk2