Problem is that all that is done in the UK, but tests cover all the wrong things and assert wrong values, and these "experienced" devs are the devs that usually pushed for wrong tests and practices. Guaranteed the post office had unit tests, but they tested everything the wrong way. Lack of skill and passion can't be compensated by practice. If everyones goes to their office to churn out features and clock in then you end up with crap.
The Post Office, HMRC, NHS, Home Office, DVSA, DVLA, Ofstead, all suffer from similar issues, as do private entities.
But at least they are all hybrid or on site so they can pretend to work by doing cheap talk and playing petty politics. British made software is like Soviet made cars.