The tape is very easy to fit, just take you time when forming it along the pipes.
You use a special tape to fix it onto the pipes, similar to a fabric tape but stronger. You could use an alternative tape as long as it is strong, wouldn't think pvc tape would do, something like duck tape may do the job. As a temporary measure to ensure the tape stays snug to the pipe you could ty-rap it, or use string or similar, once you fit the tape remove the temporary ties.
The tape does not have to be wrapped around the pipes as can be seen in a few images on the web.
Use self limiting tape as is will limit the max temperature of the tape.
Different ratings of tape are available, e.g. 10watts per foot / 10watts per metre etc.
Can also be found with the name "parallel heating cable"
One end is terminated with an end termination kit, which basically ensures that the two wires do not touch anything, including each other.
The other end, as has previously been mentioned, could be terminated onto a flexible wire, then onto a 13a plug. Not directly into 13a plug.
As you mention, you are going to use temperature switch, which is fine, but you could also consider a simple segment timer. A 24hr timer with the segments set to perhaps come on for a 15min period every hour during the night, this could be adjusted depending on how cold it is, with the setting adjustable to suit conditions.
The 13a plug is only an option, for your situation you may want something more permanent. (fixed)
Of course you are going to lag the pipes once the installation is complete
The tape can sometimes be found/used in the chemical industry, just in case you know someone in that type of job, they may be able to assist
