Categories not found when using category permalinks

my site is http://www.summerdress.org.uk.

My permalinks to categories have been messed up and are returning either a 404, or not found.

I’ve taken some advisce from the forum namely:

disabling all the plugins
move the installation to kubrik to test
resetting the .htaccess file

None of the above affect the result. Has anyone any ideas how I can remedy this?

Thanks