The beautiful but imaginary efficiency of bungled outsourcing demonstrated yet again.
Choose another sole supplier and imagine things will be better this time, despite witlessly yet again buying into the private sector equivalent of a planned economy but an economy with an important difference: it's actually designed and intended to perform inefficiently for the customer.
By sole-sourcing, we remove the single reason to put up with the inefficiencies axiomatically entailed in supporting somebody else's business plan. Only real competition provides the existentially threatening level of motivation for an external business plan to actually perform beneficially for your own.
Figure it out: the reason for Aviva's existence is to divert money from performing services or goods or whatever is on sale, as with all private sector enterprises. Profit is the objective. Yet from our perspective as customers other people's profit paid from our money is waste.
With no checks on this motivation in the form of stiff competition the story will always end sadly and badly for the customer.