A bit of progress on this today
With "twin" to compare with I could see that a resistance of 10 ohms was high, measuring across the two connection points on the HRW
It was then a matter of testing each element in turn, helped by the fact that I suspected which element may be high resistance
Element number 9 showed 1.5 ohms about 6 inches in, 6.8 ohms 8 inches in. There was no visible break, so I decided to simply get about an inch of bare wire and stick it in place with some insulating tape
Heath Robinson works, the DAB and FM signals remain in place when the HRW is switched on. The ultimate test will be in the morning when I suspect there will be heavy condensation
Then I need to figure out a permanent repair, or is the old silver paint still the best method ?