Only 1 item added to cart and error when updating quantity in cart

-- HikaShop version -- : 3.0.0_2017-02-22_17-00-15
-- Joomla version -- : 3.6.5
-- PHP version -- : 5.6
-- Browser(s) name and version -- : Chrome 56.0.2924.87
-- Error-message(debug-mod must be tuned on) -- : Fatal error: Call to a member function checkSize() on null in /var/www/vhosts/iafdesign.net/httpdocs/dev/3lab/components/com_hikashop/views/checkout/tmpl/show_block_cart.php on line 87

1. If more than 1 item is selected, only 1 is shown in the basket, this happens with all items.
2. If you then go to checkout and update the quantity, then it errors:

Notice: Undefined property: CheckoutViewCheckout::$imageHelper in /var/www/vhosts/iafdesign.net/httpdocs/dev/3lab/components/com_hikashop/views/checkout/tmpl/show_block_cart.php on line 90

Fatal error: Call to a member function checkSize() on null in /var/www/vhosts/iafdesign.net/httpdocs/dev/3lab/components/com_hikashop/views/checkout/tmpl/show_block_cart.php on line 90

3. The latest version of Hikashop has also produced errors in the back-end configuration/advanced/cart retaining period and frequency of check for the carts settings:

Notice: Undefined variable: return in /var/www/vhosts/iafdesign.net/httpdocs/dev/3lab/administrator/components/com_hikashop/types/delay.php on line 120

Notice: Trying to get property of non-object in /var/www/vhosts/iafdesign.net/httpdocs/dev/3lab/administrator/components/com_hikashop/types/delay.php on line 120

Please note we are