I will go to Windsor at 15:00 first from Staines and then Ashford (Surrey) at 18:00 tomorrow. I am going to purchase an off peak return ticket between Ashford and Windsor & Eton Riverside. However, my closest railway station is Staines. So my question is, can I use the "out" ticket (Ashford - Windsor and Eton Riverside) at Staines ticket barriers? Will I be able to go through and is this ticket valid on the journey from Staines - Windsor & Eton Riverside? Thanks.