Website crash due to potential custom code

Site URL: http://www.alexcrockford.com

Hey all. I've tried to permanently redirect my old website to my new one following the steps on Squarespace.  I tried disabling all pages, with no luck, so then tried deactivating the website. However, since deactivating the website it now crashes - its refreshes to a blank screen every time. Squarespace believe this is being caused by a custom code. The only changes I made in the website before deactivating it was to disable the pages - expect for one page which would not disable (the main home page).  Squarespace has since reactivated the website but the same error persists. 

Can anyone help with suggestions on how to a) find the possible custom code which causes the website to crash or b) have any other ideas?

Many thanks

Can you paste all code in Design > Custom CSS, Code Injection > Header/Footer? We will check easier