Previous HG and planning another pregnancy - anyone in UK had success obtaining pre-emptive antiemetics?

Hello everyone. I previously had an HG pregnancy that left me virtually unable to move from lying on the sofa until 3rd trimester - nausea/vomiting improved to tolerable levels as soon as I got ondansetron in the 2nd trimester (GP wouldn't prescribe in 1st even though 4 first-line drugs didn't work), but I had lost so much weight and my blood pressure was in my boots the whole time, hence debility.

I would love to have another child but it is a huge decision to potentially go through it again.

​​​I am aware that nowadays there are some suggestions that 'standby' meds be issued for HG folks planning another pregnancy and that ondansetron is seen as ok as second-line in the first trimester, so I am hopeful, but also skeptical about whether this actually happens in practice. Anyone have any experience getting this out of the NHS (or indeed private in UK)?