Hi,
It would be quite difficult to get the last category seen by the customer.
It's not something which could be done thanks to a simple PHP line. It would required several modifications in different views in order to store the last accessed category and create the right link for the "continue shopping".
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.