I tested 4 frames originally, which was nice, the box coming quite quickly, within 2 days if I remember correctly. Returning the packaging with the chosen carrier was weird as the website, local number and 0800 number didn't contact anyone. I had to email support to arrange the pickup. Still, wasn't a huge hassle.
My first order took maybe nearly two weeks. However when it arrived the prescription felt off. Now, technically the prescription process online was correct and legit. It turns out, the prescription I got from SpecSavers didn't have a PD value which was what was causing my prescription to feel weird. Once I had this measured I told Optically and they generously collected my glasses back and dropped the correct prescription in as a top priority. Now the specs are great.
So essentially, this process is smooth and clean assuming you get all of the relevant data and Optically gets it within their system. I do not recall having the option to put that in their online form though. Maybe someone can correct me.
Long story, short. It was a longer process that I would have originally imagined but my experience may be a bit of a one off. Would still recommend them as they were exceptionally accommodating through the progress.