Upvote:2
If the InterRail officials tell you that it is better to change the pass, it is better to change the pass.
Passports are often checked against the name on the pass in some countries and less often (to almost never) in others, and in several countries the train people will see Alex and Alexander as the same name, in other countries they may make a case out of it just because they can.
One fine and losing the pass (as it does not belong to this person, see the name is different) is likely more expensive than the name change.
Upvote:2
In case anyone else has this issue, I had the ticket changed (which cost around Β£60), but it would not have been an issue.
The tickets were checked on most trains, but not once against the passport, even for Eurostar.
In most cases, the ticket inspectors didn't really know what to do with interrail passes and just checked the dates.