The Natural Philosopher explained on 20/03/2017 :
Not only is 3.3kV used in the UK, but 2kV, 3.5kV and 6.6kV are also used.

No. Were used. Once. Not any more.

Were used, suggests were installed. Once installed they are there until
replaced - which rather suggests I was correct in the matter of the
3.3Kv, though wrong in regards to what they installed on wooden poles.