@cprgolds, yeah I've disabled Chrome extensions (I only run a lowly two of them anyway) and no luck with doing that. Really frustrating! Especially as the Menu does work really well!
I'm almost ready to video it just to show that I'm not going mad
@PayBas, I've just had another play with permissions and found the one that causes the 'No access' forums to show for Admin in the breadcrumb menu.
If I go to:
Users and Groups
Administrators drop down
First drop down > Select type: Administrative permissions
Click ' Forums' tab
And the permission "
Can manage forums
" is the one that either shows or doesn't show them for Admin. So this seems to be over riding the 'Can not see' permission set elsewhere. Either way, the 'No access' forums never show in the 'Jump box'