http://www.vehicle-wiring-products.eu/
Excellent service, the heatshrink tubing will work out much cheaper for you though and a local sparks or motor factors will probably have it.
Get the adhesive backed heatshrink if you do it that way, its ace, the tube shrinks and the glue seals it permanently, that stuff over a soldered joint looks sound to me.
The one thing that might put you off is you will have to cut the wire and solder it then, but its easy, honest.