I live in Middlesbrough and SICA/OSK is in several places round here. I thought it was just a local tag but I’ve started a new job driving all over the place and noticed the one on the m74 near Lesmahagow last week and did a search to find out more. There’s another one I’ve just spotted on a blue container on the left hand side of the m74 southbound just after you get into Dumfries and Galloway.
If you do an image search for sica graffiti the guy has definitely been around a while, it’s literally nationwide on structures, buildings and trains.