在英国申请南非签证

本人在英国是学生身份，想申请南非visitor 签证， 上网搜到官网上面的要求有以下；
1. 填BI-84表格
2. 有效护照，护照照片
3. Statement and or documentation confirming the purpose and duration of the visit. The said statement or letter MUST be as follows:

Visitor’s Visa: Signed letter of invitation from the host in RSA with a copy of the ID or residential status in RSA;

4. Proof of sufficient funds to cover the living expenses during the sojourn in the Republic in the form of:
Recent bank statement (3 months);

5. Provisional return flight Booking. NO FIXED TRAVEL ARRANGEMENTS

对于上述材料中的邀请函，是不是可以让酒店出给我， 还有那个Provisional Flight Booking国内我知道可以开预订单，英国这边也可以吗？之前买机票都是直接付款出的，如果有人知道可以麻烦告诉一下，感谢。