I have only used them for about 4 months and I don't think it has changed. I have just looked at it (not logged in under my username)
At the bottom of the home page, under prescription regulations it says the following.
We strongly recommend that you upload a copy of your prescription to the Animed site during the checkout process. Doing so will mean that we can process your order more quickly.
If you cannot upload your prescription, please make a note of your order number (shown at the end of the checkout process), write the order number on your prescription and send it to us via email, fax or post.
the above is what it said when I started. I first set up each horse ie name, breed, age etc. Then went into the prascend page, clicked on the horse name and ordered the number of tablets prescribed for that horse. It then said prescription only and you had a choice of things like they already held the prescription or upload it. So I uploaded it then, went to check out paid and got an e mail to say it was dealt with.