Disastrous diesel depreciation: your views

[leitmotiv]

Keen to get your views on depreciation here.

I bought an approved used 2014 Audi A5 3.0TDi Black Edition 25 months ago (December 2017). The car was first registered in March 2014, original list price £41,700) for £22,900. 17000 miles, perfect condition.

Valuation 25 months later I've had a valuation of c£13,200, despite FASH and being in very good condition (stone chips on bonnet, 1 minor curb on alloy). Mileage is now 42,500. Just had a major service and done the transmission oil change last Sept.

Depreciation here of c£10k in 25 months, c£388 a month.

I’d appreciate your views here:
- Did I overpay when I purchased the car?
- Is this down to diesel being less desirable?
- Something else?

For info: Previous car (approved used 2010 A5 2.0TDi s line, bought 3 years old in 2013 with 20k miles) depreciated from c£21k to £9k over 4 years with me adding another 35k miles to it, FASH. £11k depreciation over 4 years £229 PCM.

Thanks for your help!

[leitmotiv]

Thanks all for your comments, really helpful.

Equivalent 3.0 petrol is the S5 so not comparing like with like alas. Nearest equivalent is 2.0 petrol.

Considering my options on a petrol with a manual box, lighter, more chuckable and fun to drive...

[leitmotiv]

Thanks all for your sharing your experiences and views. It's really useful context for me as I decide my next move.