I think 'senior executive officer' is the second-lowest grade in the Civil Service that is not an assistant.

'Executive' in this case means 'getting on actually doing the work', and 'officer' means you are responsible for a particular job.

I know in the US 'executive' means management but when you think about what the actual word means that isn't universal.

Despite the name, Senior Executive Officer is a pretty low grade within the UK Civil Service.