FYI - I brought a USB External Stereo Adapter and I can now use my headset, its not perfect and means I cant use the 3.5mm Jacks but at least I can still use my headphones. This is the one I brought:
Sabrent USB External Stereo Sound Adapter for Windows and Mac. Plug and play No drivers Needed. (AU-MMSA): Amazon.co.uk: Computers & Accessories
Shop for Sabrent PC products at the Amazon.co.uk Computers & Accessories store.