Update to new gov.uk frontend

[sarahmwong]

Describe the solution you'd like

New frontend v5.8.0 is out with minimal changes - to change at end of milestone (may have a new release by then!)

Additional context

We should make this part of our regular process to update at the end of a milestone, and have a way of maintaining this going forward

Possibly trigger an email notification when the new front end is released each time? Need to then weigh up whether it is worth releasing depending on what has changed?