I saw it around where the M8 terminal is.
Forgot to mention in my OP, I seen FOUR XE60s within like an 20 minute span this afternoon, one on the M23 and the other three on the M14. Nice to see them become more common. I know they don't dump all 15 in service at once due to spares, buses charging, buses out for maintenance, etc. I guess the most is 5 - 6 is in service at once on average?
Prior to today, I only seen one XE60 a day on average, so seeing four of them in one day was quite nice lol