Found it in Screwfix,,,it doesn t need heat but STRETCHING to about twice its length..
Works a treat, The times I forgot to run tubing over the wire before soldering then cutting and soldering again,drove me mad,Trying to get it done quickly..
No heat required it sticks to itself with the stretching acting,waterproof as well..
And it costs about £2:50 for 3 meters,I cut it down the middle as it is about and inch wide
Amazing stuff,Like it a lot..

Well worth putting in the boot for emergencies.