Looks like I am a remote/ rural postcode and would be clobbered with a supplement
* Western Isles HS1 - HS9;
* Isle of Arran KA27;
* Isle of Cumbrae KA28;
* Kirkwall KW15 (not KW1-14);
* Orkney KW16 - KW17;
* Gigha PA41;
* Islay PA42-49;
* Isle of Jura PA60;
* Isle of Colonsay PA61;
* Mull PA62-75;
* Iona PA76;
* Tiree PA77;
* Isle of Coll PA78;
* Isle of Eigg/Muck PH42;
* Isle of Rhum PH43;
* Isle of Canna PH44;
* Shetland Isles ZE1 - ZE3;
* Isle of Man IM1 - IM9; and
* Northern Ireland - BT
I am a little surprised however to note that Northern Island is classed as rural - absolutely bizarre