My 2009 Defender (Puma) intermittently gives warning of ABS failure which will go away after a couple of engine start/stop cycles. Garage tells me there is a pump failure code showing. I suspect something sticking so is there a way of freeing things up short of spending a fortune on a new modulator?

I always find these sort of issues interesting ..... Have you asked in a transit forum ?

Try this one ... https://fordtransit.org/forum/