For general info, it is Automated Calibration Services who do the CEF cal day work:
The certificates I received says they use this bit of test kit (at least for MFT/PAT use I think):
www.transmille.com
I don't see a UK price but a USA site is saying "Starting at $13,800.00" so around £11.3k
Others I see mentioned are more affordable (for a given definition of "affordable") such as this one:
Clearly displays measurements and settings via Large LCD. For calibration of RCD, loop, insulation, earth testers and multifunction installation testers.
www.timeelectronics.com
Is it currently on sale at £4,209+VAT from here:
Calibrate RCD, loop, insulation, earth, and multifunction testers Large, clear LCD with intuitive menus Simulate RCD trip times, loop impedance, insulation resistance, and measure test voltage and currents
www.tester.co.uk
It looks less flash, so maybe less automation so not as good for quick turn-around use.
Another one I see mentioned around is this, though it is not claiming to be MFT style calibration:
You can rent or buy a Fluke 5502A from Axiom Test Equipment. Contact us for additional details.
www.axiomtest.com
Again, only a USA site coming up with a price on a quick search and they are saying it is usually sold at $22,822 so around £18.6k