Adding test to fail if query string is duplicate
Duplicate URLs whould still be picked up as well as duplicate query strings
If query strings are allowed, there should be no duplicate query strings
Removing duplicate whole URL test as it is muddying the water

Although the query string test is currently failing:

< #   Failed test 'Query string [query-string] /tmp/validate.in line 4 is a duplicate of line 3'
---
> #   Failed test 'Query String [query-string] /tmp/validate.in line 4 is a duplicate of line 3'

They look the same to me. Investigating.
Fixing query string test...

They still look the same to me, but somehow this works...
Removing duplicate query string URLs from DECC mapping

If DECC is remunged right now this will cause DECC to fail the validation - @psd is currently investigating where these duplicate query strings are coming from which should prevent them re-appearing.