Just an FYI post, so you can check with your folks for different options.
Maybe your vendors have similar choices.
I am a home user, so I use the shorts. A 40 foot continious (sp) length of casing is awfully hard to put on the horn !!!
Pricing is not at issue. But for the curious, the UKP is trading at 2.12 against the CAD dollar today. So a 22.00 CAD price would convert to about 10.75 UKP. http://tinyurl.com/q24dw
http://tinyurl.com/oqlas
The numbers in front (ergo: 30/35, etc) will be the diameter of the casing, when filled to the max.