You only needed to read the FAQs on the page that you linked to:
Q)Can this cable be used outside, like the normal drop cable used by bt or is it for indoor use only. if indoor only does maplin sell outdoor telephone cable thanks - Andy
A) Sadly we stock no external cable of any type at the moment. (this can't be used outside)
If you need to find a tradesperson to get your job done, please try our local search below,
or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Please select a service and enter a location to continue...
Are you a trade or supplier? You can create your listing free at DIYnot Local