I will visit London with a friend from October 7th to October 13th. We will go to Brighton one day and I wanted to find out how much that will cost. I went to http://ojp.nationalrail.co.uk and it showed me the following:
To Brighton: Departure at 09:25 on October 11th, £17 for two passengers.
Return to London: Departure at 19:03, same day, £10 for two passengers.
When I chose to pay, I was redirected to https://ticket.southernrailway.com where the price strangely was £57.
Why does it suddenly cost £30 more?