Hi Neil, I was planning on being on the train that arrives at Cardiff at 10.42, as it is easier for me to get to Epping to catch that one.  I will be relying on my son or d-i-l to drop me off at Epping station.  I don't mind waiting around if you would need to leave it until later to pick me up.  I haven't had a look around Cardiff for a long time.
Nell