Hmm, I think north may have a point. When this has come up before I think the standard answer was that London Midland have made a mistake in writing the restrictions
The national fares manual has this to say in the section with general conditions for off-peak returns:
NFM09 said:
Break of journey is allowed on
the outward portion of
Off-Peak tickets UNLESS
OTHERWISE INDICATED BY A
RESTRICTION SHOWN AGAINST THE
TICKET'S VALIDITY CODE, and in
all cases on the return
portion of Off-Peak return
tickets.
but for super off-peak returns the equivalent section is
NFM09 said:
Break of journey is allowed on
Super Off-Peak tickets unless
otherwise indicated by a
restriction shown against the
ticket's validity code.
So maybe they can restrict it. I wonder is it different for super off-peak returns that used to be savers, rather than this kind of super off-peak return that is genuinely cheaper than the saver equivalent.
In any case, if you remove the bit about super off-peak returns, I think my advice still stands that break of journey is always allowed on the return portion of an off-peak return.