We have an afternoon free from our tour
starting after lunch. . Would we be time to do this hike?
You would have enough time, but afternoons are not ideal hiking conditions: either too hot or too windy (cable car closure, necessitating hiking back down).
No the hike starts early in the morning
You can, but keep in mind the cable car closes at sunset. And you don NOT want to do this hike going down. If you really push it and you are fit, you can get up in an hour, but most people spend about 2 - 2.5 hours getting to the top.
Get quick answers from Hike Table Mountain staff and past visitors.