This is a great question. Many patients have a difficult time understanding the Sculptra concept and process. You have probably been informed as to how it works, so I will spare you that and refer you to my website or the Sculptra website for more details.
You must accept upfront that Sculptra treatments are a process. It will take you more than one treatment, and possibly even 4 or 5, depending on your aging process and response to the treatments, to reach your goal. The results are progressively subtle, which makes it a popular product.
Once your revolumization is completed you can expect the result to last up to two years. In the injectable filler world this is considered a long time. If you expect 3-5 years, you have been misinformed and will be disappointed. Any adverse side effects are indeed minimal and usually resolve over time. I don't know about the legalities of reference requests in the UK. Your doctor should be able to tell you whether references can be given or not. Good luck!