As Andy said, on the 170's there was a recall on the injectors and loom. I would like to think they would have all been done by now though as it was a good 3 yrs ago. If she is only doing short journeys, I would probably stick with the 140 and the 170's suffer from DPF issues. DPF's were never fitted to the 140's as standard.
Apart from that and the general MK5 stuff, service history, cambelt change etc nothing really springs to mind.
I think the one in the advert will be a 140. Generally the 170's had the twin chrome tail pipes. Best way to check, will be the engine code on the sticker in the boot or service book. BKD is 140, BMN is 170