Terracesider is right in saying that The Super League Show is only shown in the North of England, and that is the only way of viewing highlights of the weekly Super League rounds on terrestrial TV.
However, highlights of the playoffs are shown nationally on terrestrial TV as part of the BBC's "Grandstand" programme, which is shown on a Sunday afternoon (the highlights are usually about 30 -45 minutes long and will air sometime between 1pm and 6pm).
If you are somewhere with Sky, then you will also be able to view "Rugby League Raw" - a regional programme with highlights and features about the National League 1 and 2 playoffs. It's usually shown on a Friday night round about 11pm. To view it in Northern Ireland, you'll have to go to BBC1 NW or BBC1 Yorks - round about channel number 954 or something I think.
Better still, get a cheap flight over from Belfast - Leeds for about £30 from jet2.com and go to a couple of the games!