Provided you have a valid combination of tickets and you planned to allow enough time to change trains*, then no, split ticketing doesn't reduce your entitlement to Delay Repay. You are entitled to Delay Repay in just the same way as if you had held one through ticket.
You don't need to buy all your tickets from the same retailer, or through one search, to avail of these rights - nor do you need to receive an itinerary from a retailer for your entire journey. It's clearly much more convenient to undertake split ticketing in this manner, but it's not mandatory.
To get the correct compensation, you should provide the details of your full journey and all of your tickets when you submit your claim, including all the trains you intended to catch. Some Delay Repay forms don't make it very straightforward to do this, but I've found that with the system used by London Northwestern (amongst other operators) the best approach is to enter your split tickets as if they were one single ticket, i.e. enter the origin as the origin of your first ticket, the destination as the destination of your last ticket, the cost as the combined cost of all your tickets, and then attach a single picture/PDF that shows all of your tickets. For the ticket number/reference you can just enter something like 0, 00000 or 12345.
*This is called the minimum connection time (MCT). By default, the MCT at most stations is 5 minutes, but at larger stations it can be up to 15 minutes, and at some stations it can be as little as 1 minute. You can see the applicable MCT for a particular station at
BR Times. Journey planners will always allow enough time for changing trains.
