Thanks @180monkeys ! I also can't believe it and it's quite an anxious time. Fingers are crossed the next few weeks go well!
So unlike @countrypunk we knew ASA would be the problem for us with natural conception, he has 100% ASA. I'm glad we worked out why the swimmers were refusing to swim. But we can't really say why we had to try 7 embryos to get this far, possibly our age (I'm 40 now), but we do manage to create decent embryos but implantation repeatedly failed. He had a fever before round 2 and it killed all the sperm dead, so what was used was crap and the 3rd and 4th embryos transferred were very poor and the clinic said the sperm was very poor. Lesson learned, next time we tested his sample weeks before the 3rd egg collection to make sure it was ok and wouldn't end up like the second attempt.
ICSI is the process of injecting the sperm they select into the egg. IMSI is the method they use to select the sperm at some clinics, not all of them have an IMSI microscope. Our clinic, Lister, does have an IMSI microscope and this was our best cycle when using the microscope. First NHS round was 4 embryos, second private round was disastrous and we got 2 embryos (not blasts) because of his fever, and third round resulted in 5 embryos, and one of those is working. So maybe using a much more powerful microscope helped them pick the ones that weren't so damaged, stuck together, dead etc.
When they take the sample depends on the clinic. For example, on our second round we checked into the private hospital room at about 10am. By 10.45am they called him down to give the sample and then I didn't go down to theatre until about 2pm, something like that. We had the clinic analyse his sperm after this round and an embryologist called us and said they can see 100% ASA and for the next attempt the sample should be as near to EC as possible. We then arrived at the clinic for round three and there we are in the room and this time the lab manager called me in the room and said this is the plan, we won't call him yet and it will be nearer the time of your EC. She was very helpful, and maybe it doesn't make a great difference but when the sperm are all clumping together in the pot, it makes sense to me to get to prepping them ASAP. I would be tempted to ask your clinic what their procedures are for prepping ASA sperm.
28 is good! How old are you now? Mine was 36 when I started but I was 'only' getting 10-15 eggs each time, even though I technically have a lot more in there. The vitamins for men definitely do help. We saw an andrologist who recommended Impryl for DH and it did seem to help. He also took Omega 3 and Coq10. We also had a regular masturbation schedule for him, it was every day or every other day, and a shorter abstinence period before the day of the IVF sample.
I did an NHS round for the first cycle, then a private for the next two because I only had one NHS round where I live. It was very slow, and I have some regrets about not doing private while I waited for the NHS (which was allowed in my CCG). We went round the houses back and forth between the NHS and private because the NHS basically told us there was nothing wrong (lol) and refused to refer us. I started the GP testing process in summer 2020, was referred to gynae in May 2021 and had a dreadful experience with the woman I saw. I ended up having to see a private specialist in June 2021 to get a letter to take to my GP saying they'd got it wrong and we evidently did need intervention. I took the letter to my GP in July 2021 and he referred me when the gynaecologist we saw in May 2021 refused to. Funding came through quite fast, and I saw the clinic for the initial meeting in August 2021. I then had to wait from August 2021 to January/February 2022 from our first meeting to start our first round with Guys. It was a bit of a joke tbh, an expensive, 4-year very bad joke. 
I have heard there are longer waits in NI, I wonder if it's because there's fewer clinics? Not sure.