washing machine buying help please

My parents’ washing machine finally died this morning and they are looking for an efficient replacement. Having read the advice here, all the ones we’ve looked at seem too complicated.
They are a 2-person household, they use their machine approximately twice a week,with an extra bedding load once every 2 weeks. They mostly use the 40C standard wash cycle. Their main concern is low running cost and long machine life. We looked at the Which? best buys but don’t know if the 4 we narrowed it down to were the best for them (Samsung WF80F5E5U4W, Bosch WAQ28461GB, Siemens WM14Q390GB and Siemens WM14Q360GB)or if something else would be more cost-effective. Thank you for any advice anyone can give 3 confused numpties!