It took a couple of weeks but she is back on the road. I was able to buy a new pump/sender off EBay for £32 as it is a standard Ford part used in the Escort/Fiesta/Ka. My initial attempts to remove the old one were unsuccessful as it was corroded in place. But once I bought the proper removal tool it came off easily. Not unexpectedly, the union for the fuel pipes was a 'bodge'. Rather than using the official right angle join they had simply pushed the fuel pipes in.
It was very difficult to get them out and in the end I cut then off to get the unit out.
Once in, and taking advantage of the access to redo the fuel couplings, she was up and running.