1) Step away from the car when taking photos, the proportions looks better from a little distance with some added zoom. Image order needs to keep buyers engaged so you can mixed them up and you can add some finance logos, HPI logos etc for good measure.
2) Remove close up interior photos where the displays look dirty.
3) Clean the front tyres just before taking the pictures
4) Remove some BLOCK CAPITALS from your advert text and structure it a bit better. First a bit about yourself, the business, then the car basics, then the spec and options, then history, MOT etc and finally a long section about what you offer and why they should buy from you and not someone else. In the case of this car mention a careful mature owner as it is a good plus point. Add more wording and options in the advert text as it will give you a better price indicator.
5) Zuto. Your adverts show a finance APR of 19.6% compared to 7-8% of your competition so consider paying AT the £30 or so a month for your own finance example to be displayed there.
6) NEW CAMBELT+FULL SUZUKI HISTRY I get what you mean about the space but you can reword better to FULL SUZUKI SH or even SUZUKI FSH or FSH by SUZUKI to fit everything in.
7) Reply to your reviews. Thank you for your purchase, thank you for part exchanging, thank you for letting us take care of your finance, Thank you for recommending us etc
8) Round prices. Yes they increase views but sometimes put you way down in search results so maybe experiment with exact prices a bit to see what works better: £6991 looks like it's been more carefully thought and calculated than £7000 for example.
9) Work to improve your AT HIGH price indicators without having to lower your asking price. You have a black MINI Coupe £6500 that looks to me like it has Chili pack. If you were to select Cooper (Chili) as the derivative your HIGH Price will be Good or Great with all options added.
10) I'll stop here but maybe elaborate a bit on your 3 months warranty, is it parts and labour, is it free, can it be extended for longer at a price etc...
Actually I just spec checked that MINI, it does have Chili pack and a whole host of other options, the £6500 price now looks like a real bargain:
https://www.mdecoder.com/decode/t455304