You've got 10% off all the stuff at the top with the contact lens deal, including sandwich and crisps.
The next bit:
I assume sprk iswt... whatever that is was your meal deal drink? For some reason no 10% off that, but the meal deal saving was £1.37 which more than cancels out the drink cost - so at this point it looks like your meal deal cost £3.15. It's usually £3.39 but you got the 10% off two of the items before the discount (i.e. discount was applied assuming you did not have 10% off), so you either are paying 10p too much or 25p too little depending on whether you were supposed to get the 10% off and the meal deal, unless drinks are randomly excluded from the 10% off, in which case it is correct. Anyway, that is sort of irrelevant because...
Next you've got your £5 off. Simples.
Then you've got your £1.40 saving to take your meal deal from £3.39 to £1.99... except you're only paying £3.15, so you're saving an extra 14p... which actually works out as a bit more than 10%.
But then you have your shampoo, which didn't get the 10% off for some reason (either mistake or exclusion).
The receipt adds up correctly after all this to £13.86
So if you added up what you should have spent and applied savings logically, you would expect:
£1.99 meal deal
£13(=18-5) for the skin care
£0.80 conditioner
£0.20 shampoo
= 15.99
90% of 15.99 (ie 10% off) = £14.39
So in conclusion, drink and shampoo did not have 10% off, but because they applied the 10% first to the other items, then took the other savings off (meal deal and meal deal reduction) as if you had paid full price, you paid £13.86.
Done!