Kolff sent his kidney machines to several overseas units, including Hammersmith in London. The experience was described positively in print, but apparently more negatively in person. More in Dialysis in the UK in 1959 (historyofnephrology blog). Jo Joekes was the main force behind this work.
At the same time, a home-grown UK dialysis experiment was being undertaken in Southern England by an RAF doctor/ pathologist, Michael Darmady, at Salisbury.