Thanks. I sort of suspected it might be warped rotors. We have a number of different brands over here so will have to suss out which is reasonably priced for longevity and performance.
Jeep dealer quoted £141 (US$216) for a pair of Mopar front discs, but not sure how good Mopar are in comparison to other brands. Saw these
on eBay for £100 (US$152) and then these
for £60 (US$92).