If you have found a way to make passholder reservations for RENFE that is not known about then please provide details, it would help many others.

Hi there - I just get the guy recommended by Man in Seat 61 to make the bookings (for a small fee). Really easy.

Apparently requires a booking fee of £12.50 plus reservation fee. (normally £19.50) specially  for IR  users.

Seems to be a small office-or maybe even a knowledgeable individual with some contacts (like that Italiarail-a 1 or 2 person office near BOS/Mass with a connection to that TrenIt system) in GB with limited opening hours. THis means it at least doubles the total to pay and if it is open to non-islanders out of  GB is unclear.

It’s one booking fee per booking (ie ALL of the reservations for our two person multi journey interrail trip in Spain). I suppose I could have called DB and waited on hold for a looooooong time on an international number but this worked for me really well. Also - perhaos less of an issue for me as I already feel we got a great bargain with the 50% off interrail tickets. 

No problem from me but it is worth letting all members know the full picture.