Whether to go for an older or newer version varies across cars. The Astra went through various changes in its long life. Sometimes these were cosmetic but the K car was a very different car to the J, not just a mild makeover.
They also had a variety of engines (petrol and diesel) some belt, some chain cam, Also some were turbo, others not. And there are manual and auto variants.
Without knowing which engine and transmission each car has its hard to comment. However what would concern me is the partial service history. Some Vauxhalls have 20k service intervals which in itself isn’t ideal. So even a “full” service history without oil changes every 10k/year would put me off. Especially if it’s a chain cam engine.
So how partial is the service history and which engines/transmissions are these cars? As already suggested if you do want to proceed with either car a test drive is essential before committing. You can’t buy an 8/9 year old car based solely on a seller’s own condition report.

Edited by catsdad on 31/08/2024 at 02:09

<15 min commute, mostly down an A road, weekend trips away and some country driving

Doesn't sound like you do anything like the miles to warrant considering a diesel.

Most diesels are not really going to be a wise choice because of the potential for DPF problems if the car is or has been used for mainly short journeys. So even if you do the kind of miles where diesel makes financial sense (at least 12k per annum), you don't know how previous owners have used the car. And so you may be buying yourself in to a lot of imminent financial pain because a clogged DPF wont be covered by any warranty (this is even the case on new cars unless manufacturing fault). Diesels also cost more in servicing, and even setting aside DPF issues, parts will be more expensive than a petrol engine. When on a tight budget, it is all too easy to mistakenly focus exclusively on fuel economy when thinking of the running costs. But unless you are doing big miles, the overall running costs of a diesel (particularly one getting a bit older) is very rarely going to be lower than a simple n/a petrol.

1.6 CDTi BlueInjection SRi Nav vs 2.0 CDTi ecoFLEX SRi.

Between those two?, in all honesty I wouldn't touch either, regardless of how close the seller is.

You have not given the prices of these cars or your budget, but a look on Autotrader suggests an average of £2.5-5k for a diesel Astra like either of these. Working on a budget like that, there are much better choices of petrol engined cars more likely to be reliable and more likely to have cheaper overall running costs, starting with the Astra 1.6. But also a Focus 1.6, a Toyota Auris 1.33/1.6, Honda Civic 1.4/1.8, Hyundai i30 1.4/1.6, Kia Ceed 1.4/1.6.

Old diesel Astras with high mileage and under £4000. As others have said, a potential recipe for disaster.

In my area (East Anglia), £4k is well and truly banger territory. I've seen 12/14 year old Polos and Golfs for approaching £10k round here, albeit petrols with sensible mileage.

Far better to buy a normally aspirated petrol car locally, especially given your proposed annual mileage.

Buying a high mileage Diesel which is 8-9 years old is very brave. One without full service history is madness.

I hope you have £2k cash to resolve and faults when things go wrong: as they will.

How many miles a year? If under 9k then you WILL have problems.. diesels are best o motorways.

You should be looking at petrol cars.