I love Pet Bucket, I can get my dogs Heart-worm/tick treatment that also takes care of a wide variety of internal worms as well. I get it at a great price compared to here in the United States. It is by Bayer, a trusted name brand.
Since it comes from UK and passes through customs it usually takes 2-4 weeks. I have ours setup for auto refill and I set it up when I had 2 out of 6 left to be sure I didn’t run out.
I was told about Pet Bucket by the Rescue that I got our dog through. They used it for the foster pets to cut their cost and no prescription needed to get it; easier for foster parents.