 Design This study will involve an unblinded, cross-over design, with patients being randomised upon entry into one of 2 groups. The 2 groups will be - 1. HF80 dialyser this is the best of the currently used dialysers and therefore no participant will require a reduction in their dialysis during this trial; and 2. FX dialyser. Patients will have baseline tests performed prior to intervention and then repeated after 3 months. At 3 months, patients will then cross-over into the other group and tests repeated after a further 6 months. 