I went through the UK online passport renewal system last year, and it is the best website I have used in a very very long time. A real breath of fresh air. It worked perfectly on my old computer and 'ancient' browser. Everything very simple / accessible / clear, colours, text, buttons, fields, requirements. A simple step-by-step navigation and actually friendly.
It is a shame that more businesses dont care about their customers enough to invest in such a well designed website. Well done HMPO.