Thanks Monk, but as I said before, I was increasing allocated memory. Turns out my WAMP installation was giving me the wrong php.ini to edit and so memory was never increased.
HOWEVER, now that I've solved that issue, I have another: I know that I have to update my database after updating the files, however when I try to access ANYTHING in /admin, I get this error:
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DB ERROR 1054
We are very sorry, but an error has occurred while processing your request. Please try the operation again by either pressing the Refresh button on your browser, or by going back one page using the Back button. If the error persists, please contact our web development team.
The details of the error are shown below. Please quote this in any correspondance regarding this problem.
Page URL:
http://localhost/ViArt_shop/admin/admin.php
Referrer URL:
http://localhost/ViArt_shop/admin/admin_upgrade.php
Database error: Invalid SQL: SELECT setting_value FROM va_global_settings WHERE setting_type='global' AND setting_name= 'site_url' and site_id=1
MySQL Error: Unknown column 'site_id' in 'where clause'
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So clearly somewhere between 3.2 and 3.5, the DB structure changed, unfortunately, according to ViArt's manual, in order to update the database, I have to use admin_upgrade.php, which is generating the above error. So it's a catch 22, I have to update the database in order to update the database :P