Unallocated council tax bands

[KieranWitt]

From time to time, the council tax band for new build sites may not have been allocated at the point of preparing for sale/listing. Proposal to add an "Awaiting allocation" option to the question to councilTaxBand

"councilTaxBand": {
              "title": "Which Council Tax band does this property fall within?",
              "description": "Band I relates to Wales only",
              "type": "string",
              "enum": [
                "A",
                "B",
                "C",
                "D",
                "E",
                "F",
                "G",
                "H",
                "I",
                "Awaiting allocation"
              ]
            },

[jacknely]

Let me know if we should also be updating the NTS overlay with this option.

[jacknely]

just copying this from PR so we dont lose it:

I think there is still a discussion to be had here on two points:

• Do we add "Not available" to TA6 overlay as this is not valid answer in form?
• Do we add a details section when "Not available" is selected. I didnt do this here as i think it would drive another object unless we called the details notAvailableDetails. The below is probs cleaner but a breaking change:

  "councilTax": {
    "councilTaxBand": {
      "allocation": "Not available",  # A, B ...
      "details": "new build property"
    },
    "councilTaxAffectingAlterations": {
      "yesNo": "No"
    }
  },