If you read right to the end of the actual guidance from the ICO it says: --- We only use analytical cookies – if nobody consents that will seriously restrict the amount of information we can get to improve and develop our website The Regulations do not distinguish between cookies used for analytical activities and those used for other purposes. We do not consider analytical cookies fall within the ‘strictly necessar…
If you want to track, do it properly with a package installed on your own server. stop subjecting your users to Google's All-Seeing Eye just because using their Analytics is easier for you.