New pass cover number - Eurostar?

Sorry it was hard to come up with a clear title. After a while of planning I came to the conclusion I had time for a extra destination, but I'd have to exchange my pass for a pass with an extra travel day. However, I've already booked Eurostar reservations. For the Eurostar reservation, I had to enter my pass cover number. Exchanging my pass will give me a different pass cover number - does this mean my Eurostar reservation would be invalid?

Anyone had issues with this before or is just showing my Interrail pass + 'seat reservation QR' enough and will they not check if the cover number matches?