Hi Shaun, mine came from decipher tuning ltd, I got others from Viper performance, hose fittings uk, and torques uk. Ebay is a good place to search, as none of them stock everything. Make sure you know whether you are getting a flare fitting or a compression fitting, and if it is a flare fitting that your tool has space to go on to the pipe end. The link you showed is a flare fitting I believe.
Scott, thanks, a compression fitting did the job, but if I have any problems with it, I agree that welding would be a good solution.
Dave