"How to get my sons' repeat prescription?"

My son takes regular medication, he only had a few days left, normally I wouldn't have left it that low, however I had been poorly myself. I rang to order a repeat prescription on the Thursday prior to a Bank Holiday and was told I could only order one between 10am and 4pm, bearing in mind this was 4. 10pm. I explained that he only had enough until the Tuesday and the reason why and was told that they wouldn't take the request and I would have to call back at the times stated. I call back the following day in my lunch break from work only to find that it was the same time as the surgery was closed for lunch, I appreciate the reasons why, however what are you supposed to do if you work full time?