Hello Holly,
Good to hear from a fellow traveller. I honestly don't know what to expect either regarding climate etc. I have been advised probably layers as it can be quite cool at night and on early morning safari. I have also been told dress code is casual so I plan to pack for comfort!
Travellers cheques can be difficult to cash but atms are widely available: have a look at the fco travel advice section re south africa.
Travel plug adaptor can be purchased at Heathrow, I don't think the world wide one works in SA.
I have already had my vaccinations and plan to take Malarone as my malaria chemoprophylaxis.
I spoke to a couple recently who did this trip with Travelsphere and had a wonderful time.
Are you going to Zambia as well?
Hope to hear from you, see you at the airport. My connecting flight is from Belfast.
Janice