@It beggars belief that they couldn't extract just the stuff the NAO wanted
From a technical point of view, the operation is very simple
However, as mentioned, if IT is outsourced, this sort of one-off is not usually contractually defined, so you have to launch the procedure for non-standard work, which is normally slow and painful (in my experience it almost always involves having to explain what you want to non-technical people as a first step) and leads to all sorts of farcical situations, or gets bypassed
To be fair to the outsourcer, if it's not in the contract, why should they do it except following contractually agreed steps and getting paid for it, same as any other contract?