Refactor nav bar
Refactor nav bar


Former-commit-id: f540374a83b4cc765bcf08360222d3e005641249
Former-commit-id: 0102dba1d5a3480a805cf6c8163cf39bc4d4383c
Former-commit-id: 21909915ead3866eee6f1ff5bbe0f00966cf8c41
ONSdigital/florence,ONSdigital/florence,ONSdigital/florence,ONSdigital/florence