This seller has some stock of the PL2303HX if you want one.
USB To RS232 TTL UART PL2303HX Converter USB to COM Module Serial Cable Adapter | eBay
PL2303 PL2303HX USB to UART TTL Cable Module 4p 4 pin RS232 Converter. USB To RS232 TTL UART PL2303HX Auto Converter USB to COM Cable Adapter Module. 1 simple serial communication. Wire sequence is defined.www.ebay.co.uk
Cheers, Just placed an order for one of them as I will need another anyway.