In my opinion you cant trust any site selling Kamagra in the UK because to do so is illegal. Kamagra does not have a licence for sale in the UK, if it is legit Kamagra it is manufactured by Adjanta pharmaceuticals in Mumbai but I believe a fair amount that is sold online is not real and may contain other substances like plaster or chalk etc
you are able to buy Viagra or generics in this country legally from Asda, Tesco or online at Dr Fox.