Yes, however if you are crossing the border (south to north or vice versa) from private site to private site you still need to complete a GAR and fax to SB in the PSNI giving 12 hrs notice.
Regarding a previous post, you will need to book out at most larger airfields eg Belfast Aldergrove, and you won't always be handed over by ATC, though they are generally very good. Have a good trip!
BC,