Yes, you can.
If break of journey is prohibited for the ticket you wish to use, then "Train Companies will make this clear in their notices and other publications" (Source: NRCoC). That is not the case here, so you're fine!
In fact the return portions of any Off Peak category ticket should always permit break of journey, with no need to refer to notices & publications.
Off Peak Day (CDS/CDR) tickets should also always permit break of journey* on both portions, again with no need to refer to notices & publications.
(* Before simplification it was simple: CDS/CDRs allowed break of journey on both portions and this was made clear. After simplification it is no longer simple. They have now been put in the same 'category' as SVS/SVRs and you are now supposed to check for the particular ticket you are using. However we received confirmation from ATOC that the changes were not in any way going to infringe our rights in this respect, and therefore a restriction would not be imposed on these tickets. However LM have introduced their own TOC-specific CDS/CDR that has this restriction, isn't "made clear in their notices and publications", but does appear in small print and whether or not it that is enforceable is a matter of some debate, especially given that a representative of LM has recommended starting short - which counts as a BOJ! - on a ticket with such a restriction on this forum!).