Just getting back to the original post guys, i think hot versus cold has been 'done' extensively already in other posts. I think we all know (or should do) the answer is hot.
The sleeve that Ashbys use is Texsleeve part number TEXS17 (17 being inside diameter in Mm).
Sold by Mercia International
http://www.merciaint.co.uk/hose-protection-products/texsleeve/ That said, its very expensive - perhaps that's why a seemingly innocuous 25ft or 50ft from Ashbys is expensive.
The better value option is from hypex as mentioned above by carpet guy and from them the type you need is either 3/4" Flexo Pet, or F6 Pet 1/2"
Nathan