It’s available in the Izzy on droid repo, you’ll have to add the repo to the f-droid app with the following URL:

https://apt.izzysoft.de/fdroid/repo?fingerprint=3BF0D6ABFEAE2F401707B6D966BE743BF0EEE49C2561B9BA39073711F628937A

Or scan the QR code here: https://apt.izzysoft.de/fdroid/

Doctors can prescribe up to 70mg doses of Elvanse, so you shouldn’t overdose. If necessary seek medical attention, but most likely you’ll just notice it come on much more since you still seem to be trying to find the right dose for you. If you weren’t noticing anything on 30mg then you might see some positive effects at 60mg, but you should work with your doctor to find the right dose for you, taking more than prescribed once is a mistake, doing it regularly might be seen as abuse of a controlled drug.

If you’re using BTRFS and know how to/are prepared to learn, just create separate sub volumes instead of multiple partitions. Means that you don’t need to decide how to split up space between different partitions and they are easy to delete without a live USB.

I went through Psychiatry UK for mine and they were fine, although from your link it seems they are currently one of the longer waiting lists, so I would suggest trying someone else with decent reviews. I didn’t need to wait long (maybe a week) for my referral to be confirmed, unlike the other person in this thread.
I would suggest making sure that the provider is a yes on the “Authorised to provide NHS ADHD Medication Prescriptions”. You can sign up for an NHS pre-pay certificate once you are getting regular prescriptions to save on the prescription payment.