This is the stuff you put on before you go to bed and it develops overnight. It was £6.99.
You need to be fairly quick though, I took the last two (sorry) from the Tesco Highwoods Colchester store.
There was also L'Oreal Solar Expertise SPF 15 Gel for 75p, but that had all gone at Tesco Highwoods.
Sorry if already posted, searched but couldn't find.