Menus gone and editor blank

hello – this is my first go on a forum – I’ve been running a site for 3 years and never a problem until today – I updated to the latest wordpress today and all the menus have disappeared plus the editor has gone blank…
I’ve looked for the ‘disable plugin’ button to try resetting them but I can’t find it – I suspect the theme may be out of date but there’s no option to update it…

there should be 6 main menu buttons with 8 drop down menus – but now there’s only one button…I even tried the ‘reinstall 4.1.1 option but that doesn’t work

https://www.leamingtonlamp.co.uk

theme is Clubber