The Council should have tendered this contract and, if the value is over £30k including VAT, it must be advertised on the Contracts Finder website and the details of the award of the contract must also be published. Standard financial regs require three fixed-price quotes at this level, which the Council should have considered, usually in a confidential item on an agenda. The minutes of the confidential item must record details of the successful tender and an explanation of the reasons for selecting this contractor. A large contract cannot be divided to avoid the regulations.
What can you do? The internal auditor may wish to pursue this, although the relationship between internal auditors and their client may be too close for this to help you. During the public rights period at around this time next year, ask to see all accounting records. Your Council cannot refuse this request. If you are not happy with the paperwork and the explanations given, voice your concerns to the external auditor during this period in accordance with the guidance your Council should publish.