Public-sector employment in the UK is at record highs. Despite apparently cutting inputs, productivity has collapsed to the same level as 1997 in the public sector. It is wildly overstaffed/overfunded by any estimation (and to be clear, there have been no cuts...the cuts in the early 2010s were not particularly significant, around 2-3% of GDP, public spending is as high as it has ever been in the UK, it was significantly lower under Blair...the only time it has reached this level is WW2 and 1975, the financial year the UK govt was bankrupted).
DVLA isn't complex. We live in a world of regulation, rules, and standards. Almost every large business does stuff like this at a global scale. It isn't complex, it just has to be complex so the budget is filled (and Fujitsu can get their contract).