Many suppliers will supply microphone added headphones, but the cost of such a facility is usually heavy. So I went to my local "PC World / Curry's" store and purchased the below microphone ready headphones.
I then went to "Technofix UK" website "www.technoFix.co.uk" for the "pc headphones to rj45 connector" for the FT450d, and also purchased the remote PTT foot switch, this gave then both hands free to operate the radio and the computer for qsl logging.
However you do need also to purchase a 3.5mm 4 pole to twin 3.5mm 2 pole adaptor lead, the 4 pole socket for the headphones connector, and the twin 2 pole jack output, one for the radio headphones socket on the radio, while the second 2 pole jack for the adaptor lead for the microphone connection. These adaptor leads are purchasable from amazon, and most probably from other sources.
I am sure I saved some money over other supplies of microphone ready headphones for ham radio use. It would be wrong to say how much, so I will leave it to others to give a value indication.