Never too late as you can always get on: seat reservations are optional on British trains (but a good idea to make on a popular route such as Leeds - London).

Right now they're available until 26th July (90 days in advance).

Never book through ACPRail: British seat reservations are free of charge so you shouldn't use their service. Interrail/Eurail should also remove their mention altogether…

I'd make them a few days in advance for peace of mind as it's free anyway. :)

Thanks so much for your reply! So do you think the reservations will be available nearer the time? 

Can I also just check it’s ok to travel on several trains for our outbound journey? We will be doing Ilkley - Leeds, Leeds - London, London - Paris. My understanding this still counts as our one outbound journey as long as it’s all in the same travel day? 

Sorry for so many questions - it’s our first go at interrailing! :-) 

Sure, totally fine: on the outbound day you can take as many trains as you want in your country of residence. :)

Simply book the Eurostar as soon as your dates are set: extremely popular route, Olympics in Paris and passholder quota… use Rail Europe to avoid fees.

The LNER reservations will become available 90 days in advance but you can also wait closer to travel date without issues. I always made mine the day before and still changed my mind a few times. Use https://www.lner.co.uk/travel-information/make-a-reservation/

No worries and don’t hesitate to ask further questions, we’re here to help!

That’s so helpful thank you. 
I have already booked Eurostar but did it directly on the Interrail app and paid for the seat reservations - should I not have done that?! 

The Interrail/Rail Planner app cannot book anything* but I guess it redirected you to interrail.eu? It’s a totally fine and valid option. The extra 2€ fee per person quickly add up but that’s the only thing, don’t worry.

Here is a guide with the best places to book: https://www.seat61.com/interrail-and-eurail-reservations.htm

*you only log train journeys there. This can be done at any time prior to boarding.

Sorry yes you’re right, it was Interrail.eu! Ok that all makes perfect sense - thank you so much for your help. Really appreciated :-) 

As you’ll know if you live there, Ilkley to Leeds is run by Northern, who don’t have a great reputation for performance! I would leave yourself plenty of extra time if you need to get to London and catch a Eurostar. 
 

Definitely a good idea to reserve on LNER, but don’t sweat it. If you can’t reserve, or if you need to change your departure time, you can just jump on and find a seat.