Our Yaris d4d finally died after 130k requiring nothing but two wheel bearings and a new alternator. Unfortunately the glow plugs all broke snd seized in place – mot fail. Next doors Yaris was traded in for £250, another 2003 but petrol model with 75k on clock.
Friend had a Micra of similar age, that was also robust and really cheap on parts.
I would go Japanese, manual, pre faffy electrics, looked after with full s/h and not put off by high miles. I wouldn’t get too tied to a model or Japanese – check out the owner and condition.
We once looked for a fiesta, but on same forecourt was 13yr/130k Mazda 323 1.5 with a thick file of date order invoices and MOT, all in one name at the same garage, including a twice a year full valet and polish sat on front seat. We ran it for 18mths/18k, it cost one tyre and we sold it for £150 more than we paid….