Have to go to Hockley on Saturday. Have looked at GA website and they have Hare fare promo so can get a £12 return. On way out it's easiest for me to go to Manor Park and get Elizabeth Line to Shenfield then get on GA train to Hockley. Going out in Central London in the evening so want to get train back to London Liverpool St. If I get a return from London Liv St to Hockley, is it ok to get on at Shenfield. I won't be leaving the station just changing trains?