Advice please on when to book ovulation scan???

[CarbeDiem]

Hi,
I need to book for ovulation scans and I'm unsure when to book the first appointment.
The Gynae I visited last week basically advised - go on day 10-11 then again day 16-17 but she's advising for someone who has 28 day cycles.
I don't.
When I ov it's between day 10 and occasionally day 13 so if I follow the advice I'll miss it.
I will be CD 7 this friday.
Normally I wouldn't be so stressed about it and just repeat it if we missed ov but I'm temporarily returning to the UK next month so will have to wait for 3 mths to do it again here.

If the knowledgable people here know - would day 7 be too early if say I don't ov until day 13?
Should I maybe try to book for saturday? (CD8) as I think there's some ultrasound places open that I can use.

Thanks.

I've been through the fertility mill and had many scans, but I'm not sure what an ovulation scan is. What are they looking for? Follicle growth? Confirmation that you have ovulated?

Yes sorry, should have been more clear.
It's to check that I ovulate.

So they are trying to do one before ov to check there is a dominant follie and one after to check there is a corpus luteum?

In my case, day 7 wouldn't have shown much (I ovulate between days 14 and 16). There would be several follies growing and no front runner at that stage. I'd probably go on day 10. There's a chance you might have oved by then, based on what you say about your cycles, but even if you have, they should be able to see a fresh corpus luteum.

Yes that's right.
They want it done because although I'm having periods It appears that I'm sometimes not ovulating (so say the opk's and my own cervix position and fluid monitoring) and that combined with my hormones and other symptoms is pointing to PCOS :(

OK so too early is not good if there's a chance they won't see anything happening. I'll book it for monday CD10 and just hope it's not happened by then.
Thank you for replying.