I can see the sense in not using surnames, but I would say it is a difficult one to call.
I would imagine from this thread (that I started, SORRY) that most schools are using surnames or parts of surnames as part of the students username.
I would have thought there should be some clear guidelines on this sort of thing, but having done a little search I could find nothing on the subject.
Still not sure what to do now though.
A lot of our little erks can't remember their names, let alone a random code. When they get stuff like that, Educationcity for example, they write their username and password in their planner.
I use the initial of the forname - J, initial of the second name - A and surname - Bloggs with two digits of the year that they started school - 12 e.g. JABloggs12.
So far we've not had any duplicates in the year groups. If needs be I can add a third initial - B e.g. JABBloggs12.