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You could actually save time, go to boots, get the tests then send it off for analysis (obviously if its only for private and not work reasons). They've offered this service for a whioe now. I think you have to pay quite bit of money for it and also what if the samples get lost in the post - hey people nick anything these days!
I say just swallow your pride & go to a GUM clinic. Its free and probably quicker in the long run