The UK civil service is great - although it strikes me as someone really good was given the power and budget to make it happen.

The UK government however...

You are spot on there. Here is Tom Loosemore (one of the originators of the Government Digital Service) explaining how it came to be:

https://parliamentlive.tv/event/index/abfe49d3-f24c-4b93-b8e...

Unfortunately the spend control that GDS had, has been removed.