In addition, we were encouraged to throw away PoCs (that had passed the first service assessment) and start anew to make sure we ended up with a great service at the end of it. This meant that inside a pretty large organisation, testing and validating new services was relatively easy as you could cut corners on the PoC and have an institutional understanding that you'd probably throw it away entirely and start again with something more solid.
One of the mantras that was oft repeated was that 'people do not have a choice to use our service' -- because it was a service that only the govt could provide for whatever reason. The government service manual is amazing, alongside things like the service design rules (more aimed at UI/UX designers).
In addition, the entire team for a service or section thereof would participate in nearly everything. User research (actually watching users use the site) - everyone was there, from user researchers to product managers to developers and designers.
It's a shame more of it wasn't adopted by other govt dept (there are notable exceptions who have done a very good job)
[0] Plug - I worked on the new data.gov.uk
It's always so jarring to be taken back to the odd parts that are still running on the old system (mainly when digging around in PAYE / VAT stuff).
The modern GOV.UK is a breath of fresh air compared to the government's online offerings when I first started in business 8 years ago.
You're not kidding there. Every single time I go to do PAYE I get the same survey questions, even though (when I can be bothered) I tell them they could improve the site by .. not showing me the same survey every time.
Their commitment to accessibility is also laudable, unlike other commercial organisations who aren't incentivised to service that minority.
Many people complain that GOV.UK "looks boring" but it's brilliantly effective.