Can I ask how old you are OP? I've been referred to the multiple MC clinic also, its closed due to covid though. My understanding is that they will obviously take the history, when you MC, how long TTC, medical issues etc. Do several blood tests- thyroid, hormone levels, clotting disorders and possibly STI screens again. A more detailed scan/ultrasound. I already had a hycosy 2 yrs ago, so not sure if its that again, or just an ultrasound? they might do semen analysis again, but I'm not 100% sure TBH.
I was taking 400cmg folic acid for years (been TTC 9yrs in total!). This last pregnancy I had IVF, and they said I should have been on the 5mg one! I'm early 40's and BMI is overweight, but not obese and no history of neural tube disorders. If you only need the regular dose, you can get a pregnancy multivitamin from Tesco and asda which contains almost the same ingredients as pregnacare, but its much cheaper.
I'm also looking into CoQ10 or the purer form ubiquitol. I've read it can improve egg quality, but there is only limited data. I spoke to the IVF consultant today. He agreed that there isn't enough evidence to advise everyone to take it, but if its not too expensive, its worth a try and cant do any harm!
best of luck 