Note that this should not affect the trains to/from Culham, only the high speed (longer distance) services.
As they say towards the end of their e-mail below:
There is no change to our local services
‘…our new cycle policy for our long distance High Speed Trains, which takes effect from the start of the summer timetable on 16 May. To give cyclists a guaranteed space, we are introducing compulsory bicycle reservations on these trains…’
However we don’t know if they’re going to start getting stricter about the number of bikes on the local trains to/from Oxford, Radley, Didcot etc. Please be aware if you travel to site by train with your bike and forward to anyone else you think might be interested.
Sent: 11 May 2016 16:29
To: Tingley, Anne V
Subject: GWR cycle policy update
I thought it might be helpful to update you on our new cycle policy for our long distance High Speed Trains, which takes effect from the start of the summer timetable on 16 May. To give cyclists a guaranteed space, we are introducing compulsory bicycle reservations on these trains. This will bring us in line with other long distance operators and we will compensate customers if we do not provide them with their booked space.
Reservations remain free and can be made online, by phone (0345 7000 125) or at a station when booking a ticket. Reservations can also be made after the ticket is purchased by phone or at a ticket office. This should be done by 18:00 the day before departure, although we can take bookings on some services up to 2 hours before departure.
We would like to encourage pre-booking as much as possible, but we understand that there will be times when booking has not been possible and there is space is available on board.
Station staff have been briefed to allow bikes on board if this is the case. Customers should not therefore have any issues travelling without booking a space for their cycle if there is space on board.
There is no change to our local services, and no limit to the number of folding bikes we can carry because these can be stored in the luggage racks. We are installing Brompton Docks at more of our stations, so that customers can hire a folding bike. We are also increasing bike racks at some stations for customers who do not want to take their bike on board.
More information and the cycle policy booklet are available on our website; https://www.gwr.com/your-journey/journey-information/on-board/cycles
If you have any questions, please do get in touch.