Ferg said he purchased striped heat shrink tubing from UK.
Here is at least one UK supplier:
http://www.finishrink.com/general-purpose-heat-shrink-tubing.html
And a Chimna Mfg.:
http://www.made-in-china.com/showroom/cjds888/product-detailgeFxWLRYazVP/China-Yellow-amp-Green-Stripe-Heat-Shrink-Tubing-YGDRS-1-.html
Y10-04-16