Thank you for being so nice, everyone 
Marmite, your Friday test was the LH surge extraordinaire and from that point you had between 24 and 36 hours to get sexing before the egg was released. Saturday's is strong, too, but that is to be expected only half-a-day (12hrs) later. This is why the advice on the packets tell you to not pee on any more opk's after you have spotted the proper surge; anything peed-on after that just becomes confusing.
Babs, I've never been failed by the cheapie internet HPTs that cost about three quid for six million
Beansprout, I once read somewhere that, for every half hour later (or earlier) you take your temp, you can expect your temperature to be .05 of a degree higher (or lower) than it should. This means a two-hour lie-in can result in a temp of, say, 36.80 when you would expect it to be 36.60. I hope I have my digital points right; I am to maths what the Pope is to sex therapy.
Welcome, emma 
I am so bored of the 2ww. I hate having a luteal phase of fourteen days (a day longer than usual thanks to Clomid). Can you imagine being 43 with one fallopian tube? The odds of getting preggo each month are so tragic I don't know how I keep my head out o' th'oven....