Hi Gareth,
I have just had a quick look at the ONE website. I typed in the journey that you are planning on 8th August and the cheapest single fare option it came up with on the 07:35 was £27.50 for a "Standard Open Single". The £6.00 "One Standard Advance Single 1" was shown in the list but was not actually available for that particular train (or any others that I could see up to 09:56)
Maybe I was doing something wrong?
