You could get an oil analysis done.

Not very expensive and it'd either give you leverage with the dealer, or peace of mind, depending on the results.

I've never had one done myself since my cars aren;t worth much, They are very popular with oil-obsessed Americans (where they are perhaps cheaper) but I;d think you could get one done in the UK .

You want one that reports viscosity (which they all will) and fuel dilution, the latter preferably estimated by gas chromatography rather than flash point, which is innacurate

EDIT.

www.theoillab.co.uk/product-category/oil-testing/e.../

I did a quick ..G.oogle and the cheapest test offering fuel dilution from the above place is 50 quid, not peanuts but you might be able to get that down a bit by shopping around.

You might try sniffing your dipstick for petrol smell, or...er...getting someone perhaps more experienced to do so.

Theres also a crude chromatographic oil test called the "blotter spot test" but its quite difficult to interpret.

ENDEDIT

Edited by edlithgow on 25/12/2017 at 14:44

Or you could just nip into the dealer on Wednesday and ask them to sort the issue/clarify what's going on.

Depends on your level of confidence in the dealer.

I've never had any dealing with..er..that kind of dealer, apart from reluctantly buying parts from them very infrequently, but on general principles, and based on what I hear, I wouldn't want to bet a lot of money on one doing the right thing.

My new swift 1.0 litre boosterjet SZ5 told me it wanted a oil change after 232 miles and 6 weeks old. The supplying dealer just told me to reset the oil change on the dash. During pdi, it does seems that the oil change has not been re-set for 12 months from that point.

Anyway how are people finding there new swift? 1.0 litre boosterjet engine is a gem.

Edited by Grease_monkey on 04/02/2018 at 16:43